From Jason Hood
Psalm 19: The Psalmist fuses two meditations: one on the majesty of God’s creation, and the other on the Law (Torah, “instruction”) of God. Both of these areas are “revelations” from God, displaying his awesome power and guiding us to believe, trust, and live in awe of this great God. Of course, the greatness of God displayed in his creation doesn’t tell us and (because of sin) can be misinterpreted; so we need more than the beauty of nature: we need our hearts enlivened and our eyes opened by God’s instruction so that we can accurately perceive our need for him and the direction he wants us to pursue.
Psalm 20: The Psalmist joins God’s people in praying for the king’s welfare and for the success of his plans. It’s worth reflecting on how we might apply this to our government (as we’re instructed in the New Testament, and as modeled in Jeremiah 29); our church and the church universal (esp with Jesus as the King of the church, whose plan is to bring his kingdom so that God’s will is done on earth as in heaven and his name is sanctified everywhere); and in our families and vocations (as we plan and work to bring God glory and benefit ourselves and others). The Psalmist believes that the key to success is God’s salvation, which he can bring with his infinite power (v 6); our only response to this is faith—throwing ourselves into his hands and trusting in his timing, his method, and his victory (vv 7-8).
Psalm 21: Where are you finding joy and security? The King of Israel is finding his joy in God’s strength and salvation, and his security is found in God’s actions on his behalf. Christ, the King, was given these blessings by God and saved from death and poverty and obscurity, “given his heart’s desire”. Now we can share in his victory, and we discover that his heart’s desire is us: that we may know him, love him, serve him, and reign with him in splendor.
God is not only able to bless and save those who give themselves to him. He is also able to judge rebels, so that he can discover who is rebelling against him (v 8) and judge them (vv 9-10) so that their plans against him are frustrated and their assault on his kingdom is turned back (vv 11-12).
The Psalm concludes (v 13) with praise for God’s greatness: if we can rely on him, shouldn’t we praise him?
Deuteronomy 1:34-46: When we read in conjunction with Psalm 21, we learn that God’s ability to judge isn’t just applied to outsiders: it also applies to the presumptuous and rebellious people who assume he’s rubber-stamped their desires and plans; or to those who assume God is on their side regardless of their high-handed rebellion against him. It’s worth noting in passing that God has plans for his people’s warfare, he does not give them carte blanche to invade and fight with whomever they wish.
Finally, we should consider how God’s rehearsal of his greatness also includes rehearsing the sin of his people. There’s a fine line between wallowing needlessly in sin and despair of self, and setting our sin before our eyes so that we remember the righteousness and salvation that only comes from God. Israel’s salvation (entering the land) came through Joshua; our salvation (entering New Creation) will come through Jesus (Joshua/Yeshua’s New Testament namesake).