In its note on Psalms 40-41, the Zondervan NIV Study Bible states: "Book I of the Psalter closes with two psalms containing 'Blessed is the man who' statements (Psalm 40:4; Psalm 41:1), thus balancing the two psalms with which the book begins (Psalm 1:1; Psalm 2:12). In this way, the whole of Book I is framed by declarations of the blessedness of those who 'delight in the law of the LORD' (Psalm 1:2), who 'take refuge in him' (Psalm 2:12), who 'do not look to the proud' but make the Lord their 'trust' (Psalm 40:4) and who have 'regard for the weak' (Psalm 41:1)—a concise instruction in godliness."

Some Bible commentators have proposed that Psalm 40 itself is actually two separate psalms combined into one—a conclusion deriving from the fact that verses 1-10 praise and thank God for deliverance He has brought while verses 11-17 lament and plead with Him for deliverance that has not yet come. Moreover, most of this latter section (verses 13-17) is substantively identical to Psalm 70. Yet we may recall that Psalm 27 was also a combination of thanksgiving and lament. As in that psalm, the idea here may be recalling God's past deliverance to muster confidence that He will deliver David from his present circumstances. Zondervan states in its introductory note on Psalm 40: "The prayer begins with praise of God for his past mercies (vv. 1-5...) and a testimony to the king's own faithfulness to the Lord (vv. 6-10...). These form the grounds for his present appeal for help (vv. 11-17...)."

Psalm 70 is probably best explained as a borrowing of part of the lyrics of the appeal section of Psalm 40 to stand on their own as a different song—or at least a special rendition. (The tune was probably different since the words have been altered somewhat.)

As we will see, David's words in Psalm 40 foreshadowed the circumstances of the Messiah, Jesus Christ, as the book of Hebrews quotes Psalm 40:6-8 as referring to Him.

In verse 1, "the Hebrew translated I waited patiently is literally 'waiting I waited" (Nelson Study Bible, note on verse 1). Though time was moving on and no rescue seemed forthcoming, David still trusted. He would not give up hope in God's deliverance. And his confidence was well placed—for God did deliver him.

The "horrible pit" of verse 2 could represent death. The Expositor's Bible Commentary states: "The 'pit' is a frequent synonym of Sheol, the grave (Psalm 88:3; Proverbs 1:12; Isaiah 14:15). In the 'pit' people are powerless (Psalm 88:4), held down by the slime and mud (Psalm 40:2)" (note on Psalm 88). Yet here in Psalm 40 it may simply represent a seemingly inescapable situation into which he was sinking lower and lower (compare Psalm 69:2)—as contrasted with him then being lifted from the mud and set upon a rock (Psalm 40:2). Perhaps a double metaphor is intended. Jesus may have been alluding in part to this verse when He spoke of establishing His Church on a rock (i.e., Himself) so that the gates of Hades (the grave) would not prevail against it (Matthew 16:18). And given the messianic prophecy of this psalm, we may also see in all these verses Jesus thinking of times God the Father had previously delivered Him as He prayed to God while enduring His final trial.

David next states that God "has put a new song in my mouth" (Psalm 40:3a). God may have inspired him to compose an entirely new psalm. Or David may have meant that God gave him a sense of renewed wonder and appreciation accompanied with renewed energy and joy (see the Beyond Today Bible Commentary on Psalm 33:3). And from David's praise and rejoicing, many would realize what God had done and would be led to place their trust in Him (40:3b)—the key to blessing and happiness (verse 4).

David declares that no one can understand the enormity of God's works or of His thinking (verse 5). How many thoughts He has. How He organizes His thoughts. What He thinks about each of us. "The things You planned for us no one can recount to you; were I to speak and tell of them, they would be too many to declare" (verse 5, NIV; compare 139:17-18). God does reveal some of His thoughts and intents concerning His people—and they are wonderful: "For I know the thoughts that I think toward you...thoughts of peace and not of evil, to give you a future and a hope" (Jeremiah 29:11).

David then mentions his understanding of what God is really looking for from people. It was not the physical sacrifices of the sacrificial system but a desire to follow His way—a desire David himself had (Psalm 40:6-8). The words here, describing various offerings in the sacrificial system generally, may have followed his presentation of a ritual offering. Verse 6 should not be understood to mean that there was no actual requirement for physical sacrifices. There certainly was at that time—but only as part of a desire to obey God. What God required was not the sacrifices and offerings in and of themselves—but a heart of obedience from which sacrifices and offerings would naturally flow as God so determined. David surely remembered the story of Samuel correcting Saul for failing to grasp what God thinks is important: "Has the LORD as great delight in burnt offerings and sacrifices, as in obeying the voice of the LORD? Behold, to obey is better than sacrifice, and to heed than the fat of rams" (1 Samuel 15:22; compare also Psalm 51:16-17; Jeremiah 7:22-23). We will see more about this in going through Psalms 50 and 51.

David recognizes in Psalm 40 that rather than just a token physical offering, what God really wants is the devotion of David's entire self. So David offers himself as an offering (compare Romans 12:1; 2 Corinthians 8:5). He says, "Behold I come; in the scroll of the book it is written of me" (Psalm 40:7). What was David talking about? It concerned having God's law written in his heart (verse 8). Perhaps he realized that the Torah (the Law) and indeed all of Scripture was written for him personally, just as it is for all of us—to describe the character that he and all of us must have. But in David's case there may have been more to it. As the Lord's anointed king, David had to write out on a scroll his own personal copy of the Book of the Law, keeping it with him and reading it all his days, internalizing it and living by it for the sake of himself, his kingdom and his family (Deuteronomy 17:18-20). So David expressed his continuing commitment to fulfill all of it.

Of course, the One who completely and absolutely fulfills all of Scripture's requirements, including the sacrifices and the ultimate role of Anointed King—who presented Himself before God as the very quintessence of all offerings—is Jesus Christ. And in the book of Hebrews we see Psalm 40:6-8 quoted as the words of Jesus (Hebrews 10:1-10)—as they in fact were, David having been inspired by Him—and are told that the entire sacrificial system pointed to Christ's ultimate sacrifice. Jesus lived His life wholly dedicated to God and then offered Himself as the true atoning sacrifice for the sins of all mankind. Psalm 40 is thus a messianic psalm—making the rest of it likely applicable to Jesus as well.

It should be noted that the second line of verse 6 as translated from the Hebrew Masoretic Text, "My ears you have opened [or 'dug' or 'pierced']" (to hear and accept God's law, it would seem), is not quoted this way in the New Testament. Rather, the same translation found in the Greek Septuagint is given: "But a body You have prepared for me" (see Hebrews 10:5)—that is, to offer up to God. In a footnote on Psalm 40:6, Expositor's says that the Septuagint rendering "represents a paraphrastic interpretation of a difficult Hebrew phrase" (that is, it paraphrases what seems to be the point here based on surrounding clauses). Even if not technically accurate (though it could be), the Septuagint rendering used in the New Testament is true and is certainly implied in context—that God wanted not animal bodies but David's own body presented as an offering for serving God's purposes (and, in ultimate fulfillment, that the body of Jesus Christ was to be the consummation of sacrificial offering—in both life and death).

David goes on in Psalm 40 to remind God of what he has done since being saved from death. "O LORD, you Yourself know..." he says at the end of verse 9. And what had he done? Besides determining to continue in obedience to God, as we saw in verses 6-8, we further read that he saw the need to spread the word about God and His deliverance. David was the king of Israel and a prophet. He had a great responsibility to teach His people. "I have proclaimed the good news of righteousness in the great assembly" (verse 9a). That is, he hadn't kept it to himself but had proclaimed it to the throngs at the temple gathered for worship.

Interestingly, the phrase "proclaimed the good news" is found in the New Testament as "preached the gospel"—and Jesus Christ, prophesied in this psalm, certainly did that (as did those He commissioned with the same task). Note that David uses the phrase "good news of righteousness." Expositor's notes on verses 9-10: "The Lord's righteousness (sedeq) is expressed in any act ordered on behalf of his people's welfare and the execution of his kingdom purposes. By his righteous acts they are delivered, prosper, and enjoy the benefits of the covenant relationship.... Righteousness in this sense is synonymous with 'salvation' in the broadest sense. The nature of God's righteous acts is explicated by the other perfections. He is faithful to his covenant people, in accordance with his promises (Psalm 33:4), resulting in the 'salvation' of his people."

David further stated how he declared God's faithfulness and salvation and hadn't concealed the truth from anyone (Psalm 40:10). We should realize that one important way David proclaimed all this is through these very psalms we are studying. He composed them to be performed publicly—so the people could learn from them, learn to sing them and join in. And again, we should further consider that the One who inspired not just Psalm 40 but all the psalms was the living Word of God, who later became Jesus Christ.

In the remaining verses (11-17), David makes his present appeal, seeing his troubles as the result of his sins (verse 12) and enemies who want to destroy him (verses 13-15). Though it is not specifically stated, it could be that his present crisis is serious illness, as in the other three psalms of Book I's concluding group of four—his weakened state and isolation giving opportunity to his enemies to rise up.

Jesus Christ, we realize, committed no sins—but He took the sins of the whole world onto Himself when He was crucified. In that light, it is interesting in verse 12 that David does not ask for forgiveness (as Christ did not need to). David merely speaks of his iniquities overwhelming him. Perhaps David had already repented but still saw what was happening as the consequences of his sins. Yet when applied to Christ, this would mean that the sins of others (including David's)—now committed to Christ as the sin-bearer—were bringing on Him the horrible consequences He had to face at the end of His human life. And of course Jesus had to face taunting enemies just as David had to (verses 13-15).

In verse 16 David declares that even in the midst of troubles, those who love God and His salvation should "say continually, 'The LORD be magnified!'" This gives further explanation to the first part of the psalm and argues in favor of Psalm 40 being one psalm.

David closes in verse 17 with a final appeal. The reference to himself as "poor" is not meant materially (see also Psalm 34:6; Psalm 41:1). The sense here is of being lowly and oppressed—of being "weak" instead of powerful (see Psalm 41:1, NIV). David is speaking of his condition of humility and abasement (and perhaps poor health)—and, as he also says here, his grave need for help. The help he needs can come only from God, and he prays that God will intervene quickly—as Jesus must have prayed during His final ordeal (and as all of us should pray during our trials today).