If one stops to think about the fact that the Psalms are the “hymnal” for the worship of God in the temple, then it seems fitting that those psalms be theologically correct. As is so often the case in modern day use of songs, so it was in ancient times that people can and do receive their understanding of God through songs. Whether it is the tune or the catchy phrasing or the way it simply relates to a person’s mental or emotional state, songs and psalms penetrate the heart and influence the mind. And so, as Tucker wrote: “The tôrâ of Yahweh functions as the fundamental guide that leads one into the way of the righteous.”
From the opening Psalm, one is faced with this fundamental guide that leads to righteousness.
Blessed is the man who walks not in the counsel of the wicked,
nor stands in the way of sinners,
nor sits in the seat of scoffers;
but his delight is in the law of the LORD,
and on his law he meditates day and night.
He is like a tree planted by streams of water
that yields its fruit in its season,
and its leaf does not wither.
In all that he does, he prospers. (Psalm 1:1-3, ESV).
Thus, the psalm immediately points the reader/singer to the law. It calls upon the person to meditate on it and to live it if he/she desires to be stable and prosper. Spurgeon was correct when he wrote,
This Psalm may be regarded as The Preface Psalm, having in it a notification of the contents of the entire Book. It is the psalmist’s desire to teach us the way to blessedness, and to warn us of the sure destruction of sinners. This, then, is the matter of the first Psalm, which may be looked upon, in some respects, as the text upon which the whole of the Psalms make up a divine sermon.
For this reason, the Torah—the Law of God—frequently comes up in the Psalms. While Tucker is correct that, “There are only three such psalms in the Psalter: Psalms 1; 19; 119,” there are many direct and indirect pointers to the Law, the Mosaic Covenant, and the need for instruction. For example:
O LORD, who shall sojourn in your tent?
Who shall dwell on your holy hill?
He who walks blamelessly and does what is right
and speaks truth in his heart;
who does not slander with his tongue
and does no evil to his neighbor,
nor takes up a reproach against his friend;
in whose eyes a vile person is despised,
but who honors those who fear the LORD;
who swears to his own hurt and does not change;
who does not put out his money at interest
and does not take a bribe against the innocent.
He who does these things shall never be moved. (Psalm 15, 1-5, ESV).
If one were not closely reading he may miss the fact that these are issues dealt with in the Psalm are also those which are throughout the Torah, but especially in Leviticus and Deuteronomy. Laws against slandering (Lev. 19:16) and doing evil against the neighbor (Exod 20:16-17) are part of the covenantal law. Honoring the Lord (Exod 20:1-11), fearing the Lord (Deut 10:12-13), are the very foundations of the Law. Interest and bribery are not simply social issues of the day, but commands to be lived by within the Torah (Lev 25:35-38; Deut 16:19).
Psalm 25 mentions the covenant ever so briefly:
All the paths of the LORD are steadfast love and faithfulness,
for those who keep his covenant and his testimonies (v. 10, ESV).
Hearkening back to Exodus 34, where God makes the emphatic statement that He is a God of steadfast love and faithfulness, but also that He will judge justly those who break His law–those who break covenant with Him (vv. 6-7, ESV). The interesting part of the Exodus account is that when Moses heard this (along with seeing the back of God), he fell down and worshiped. “And Moses quickly bowed his head toward the earth and worshiped,” (v. 8, ESV). The very truth that God expressed is what led to worship is made clear in verses 9-10. Thus Moses did according to the covenant, what the psalmist was doing and expected the singer to do as they read/sung Psalm 25: worship in light of God’s steadfast love and faithfulness according to the covenant.
Psalm 37 ought to bring one to remember the words of God as the people were soon to enter the land of Canaan. “Do not say in your heart, after the LORD your God has thrust them out before you, ‘It is because of my righteousness that the LORD has brought me to possess this land,’” (Deut 9:4a, ESV). It is clear that the people were not righteous. However, it is just as clear that if the people would be righteous, they themselves would not be thrust out of the land, but would keep it as their inheritance (Exod 20:12, Deut 29:1-9). Thus when one sang the following words, being familiar with the Torah and the Covenant, they ought to have been putting God’s Word straight into their hearts and minds (as verse 31 will state), so as to live the very truths that came from their lips.
Turn away from evil and do good;
so shall you dwell forever.
For the LORD loves justice;
he will not forsake his saints.
They are preserved forever,
but the children of the wicked shall be cut off.
The righteous shall inherit the land
and dwell upon it forever.
The mouth of the righteous utters wisdom,
and his tongue speaks justice.
The law of his God is in his heart;
his steps do not slip. (Psalm 37:27-31, ESV).
These psalms mentioned do not even begin to mention the historical psalms in which the history of Israel or history of the cosmos is recounted, which would once again bring with them the notion that the God to whom they sing or of whom they hear others sing, is the creator God and covenant God who sustains them.
Finally, one quick word about Psalm 119. As Tucker wrote, “Psalm 119 is the Torah psalm par excellence.” Each set of eight verses are alliterated with the Hebrew alphabet. Each verse within the first 8 verses start with Aleph (the first Hebrew letter), then the second set of eight verses start with Beth (the second Hebrew letter) and so on down the line. Not only is this chapter the longest chapter of the Bible, but it is 176 verses pointing one to the excellencies of the Law—the Torah. Some of the most memorized Scriptures come from this text: “Thy word is a lamp unto my feet and a light unto my path,” (Psalm 119:105). “Thy word have I hid in my heart that I may not sin against God, (Psalm 119:11). “Open thou mine eyes that I may behold wondrous things out of thy law,” (Psalm 119:18). This entire psalm was to bring the worshiper to revere and love God’s law, His statutes, His precepts, and His rules.
Within the Psalter, the hymnal of the Jews, the worshipers were taught to worship God but to do so according to the Law and the Mosaic covenant. Calvin wrote, “There are. . .two things which the prophet [writer of Psalm 119] mainly aims at; the exhorting of the children of God to follow godliness and a holy life; and the prescribing of the rule, and pointing out the form of the true worship of God, so that the faithful may devote themselves wholly to the study of the Law.” The same could be said about all the psalms quoted here in this post, and many more. The Book of Psalms is a book built upon the premise of the Law and the Covenant(s). One cannot read/sing for long without standing upon some truth directly or indirectly linked to the Torah.
 W. D. Tucker, Jr., “Psalms 1: Book of,” in Dictionary of the Old Testament: Wisdom, Poetry and Writings ed. Tremper Longman III and Peter Enns, (Downers Grove, IL: InterVarsity Press, 2008), 585.
 Charles Spurgeon, The Treasury of David: Volume 1, (Grand Rapids: Baker Book House, 1977), 1.
 W. D. Tucker, Jr., “Psalms 1: Book of,” in DOT: Wisdom, Poetry and Writings, 585.
 Ibid., 585.
 John Calvin, Calvin’s Commentaries: Volume VI, (Grand Rapids: Baker Books, 2005), 398.