Adam Clarke on Psalms 55:22

Cast thy burden upon the Lord - Whatever cares, afflictions, trials, etc., they may be with which thou art oppressed, lay them upon him.

And he shall sustain thee - He shall bear both thee and thy burden. What a glorious promise to a tempted and afflicted soul! God will carry both thee and thy load. Then cast thyself and it upon him.

He shall never suffer the righteous to be moved - While a man is righteous, trusts in and depends upon God, he will never suffer him to be shaken. While he trusts in God, and works righteousness, he is as safe as if he were in heaven.