v.2: my rock, fortress, deliverer: That which I stand on, find refuge in, am redeemed by. Which is also identity, protection and salvation, respectively.
v.7: Then the earth shook and trembled; the foundations also of the hills moved and were shaken, because he was wroth. This seems to align with Matthew 27:51-53.
v. 8: The commandment of the LORD is pure, enlightening the eyes. This is set against what Eve in Eden saw of the fruit of the knowledge tree. Genesis 3:6 - that it was pleasant to the eyes. Eve made the commandment of the LORD impure.
v.9: The fear of the Lord is not something you are involved with only when you are a sinner. It is everlasting from prefall to the new heaven and Earth, because it is as clean as the creator-creation distinction.
v.19: Who are the elects? The ones whom God delights in, not because of merits (neither strength v.17, and certainly not of ends instead of means: rewarded vs. deliverer v.20,24).
v.31: "who is a rock..." - ומי צור can be translated as "who is strong/mighty..." The Indonesians (IBIS) translated צור as pembela (defender).
v.43-45: Unlike Solomon who mingled with the strangers, David neither mingled nor submit to them, but ruled over them, made by God, before God. A true type of Christ.
v.45: The strangers shall fade away...Those whose motive were never truly to serve God before men, before David. For true submission (v.44) will remain strangers no more.