John Gill Commentary Psalms 40:17

"But I am poor and needy; [Yet] the Lord thinketh upon me: Thou art my help and my deliverer; Make no tarrying, O my God." — Psalms 40:17 (ASV)

But I [am] poor and needy
As Christ was literally, (2 Corinthians 8:9); and in a spiritual sense, when deserted by his Father, forsaken by his disciples, and surrounded by his enemies; and had the sins of his people, the curse of the law, and the wrath of God upon him;

[yet] the Lord thinks upon me ;
thinks good for me, as the Targum; or thinks highly of me; has me in great esteem though despised of men, and in such a suffering state;

you are my help and my deliverer ;
he believed he should have what he prayed for, (Psalms 40:13); see (Isaiah 50:7–9);

make no tarrying, O my God ;
which is a repetition of the request in (Psalms 40:13).