v1-2: David's heart was overwhelmed, by his own sin and sorrow (2 Sam 12), and by Amnon and Absalom (2 Sam 14); he felt that God was far away.
His response was to trust in God; we look to Christ, who is the Rock. Our weaknesses are the opportunity for His power to be manifest. He is "higher than I," for He is different, not brought low by those things that affect us so much.
v3-4: The psalmist describes a place of security and safety; abiding in Christ, enjoying a closeness with Him. This was his decision, "I will abide...I will trust..." The place of safety is described: shelter, strong tower, tabernacle, shelter of your wings. This is God's gracious provision for His people.
v5-6: See 2 Sam 7, where God gave David many promises, and David recommitted himself to follow God. Faith in God is to do with relationship, not duty and rules.
v7: The need of constant preservation; life continues only in the will of God.
v8: Sing praise forever, daily perform my vows; each day and every day; an everlasting relationship with the eternal God.