John Gill Commentary Psalms 30:10

"Hear, O Jehovah, and have mercy upon me: Jehovah, be thou my helper." — Psalms 30:10 (ASV)

Hear, O Lord, and have mercy upon me
By lifting up the light of his countenance again upon him; by manifesting and applying his pardoning grace to him, and by delivering him out of all his afflictions;

Lord, be you my helper ;
in this time of trouble; for he knew that vain was the help of man; and he was entirely in the right to betake himself to the Lord, who was able to help him, when none else could.