From Mark Booker
Psalm 17: Note where the psalmist seeks refuge from his adversaries: at God's right hand (v7). We often seek it in our own plans for revenge, but David seeks it from the Lord. He asks to be hidden under God's protection (v9). The wicked are arrogant (v10). They have no pity (v10). Their "portion is in this life" (v14). In contrast, the psalmist "shall be satisfied with your likeness" (v15). God is his portion (see Ps 73.26). As such, he holds fast to God's paths (v5).
Psalm 18: David has been rescued from the hands of Saul and he rejoices in the protection of the Lord (Yahweh - Israel's name for God): his strength, rock, fortress, deliverer, God, shield, and stronghold (all in vv.1-2). The claim is that God is a warrior who rescues the righteous king from his enemies. The idea of the king being rescued by the God who lives (v46) and of foreigners coming under this king (v45), points to Jesus, the great King whom God vindicated in the resurrection.
Exodus 13.17-22: The Lord who rescues will also lead. Israel has just been freed from Egypt but they now need direction and guidance. God provides that through the pillar of cloud by day and the pillar of fire by night. These are referenced in Deuteronomy 1.33 to encourage Israel to walk by faith and enter the promised land. Like Israel, we've been rescued from slavery, to sin and death, and given God's guidance, in the Holy Spirit, as we journey through the wilderness, a world that rejects God's rule, to the promised land, the new heavens and the new earth.