Psalms 40:1

In these verses we have, I. The great distress and trouble that the psalmist had been in. He had been plunged into a horrible pit and into miry clay (Psa 40:2), out of which he could not work himself, and in which he found himself sinking yet further. He says nothing here either of the sickness of his body or the insults of his enemies, and therefore we have reason to think it was some inward disquiet and perplexity of spirit that was now his greatest grievance. Despondency of spirit under the sense of Gods withdrawings, and prevailing doubts and fears about the eternal state, are indeed a horrible pit and miry clay, and have been so to many a dear child of God. II. His humble attendance upon God and his believing expectations from him in those depths: I waited patiently for the Lord, Psa 40:1. Waiting, I waited. He expected relief from no other than from God; the same hand that tears must heal, that smites must bind up (Hos 6:1), or it will never be done. From God he expected relief, and he was big with expectation, not doubting but it would come in due time. There is power enough in God to help the weakest, and grace enough in God to help the unworthiest, of all his people that trust in him.

— Matthew Henry's Concise Commentary (public domain)