But as for me - literally, “And I.” The meaning is, “And I, who so confidently now trust in God, and believe that he is good, was formerly in a far different state of mind; I was so hesitating, so troubled, and so doubtful, that I had almost entirely lost confidence in him as a wise and just moral governor.”
My feet were almost gone - I was just ready to fall. Of course, this refers to his state of mind. In regard to his faith or confidence in God, he was like a man standing in a slippery place, and scarcely able to remain upright.
My steps had well nigh slipped - The expression rendered “well nigh” means “like nothing,” or “as nothing;” that is, in reference to firmness it was as if there was “nothing” left. There was nothing which would keep him from slipping. The word rendered “slipped” means “poured out.” That is, in his going he was like water poured out, instead of being like something solid and firm. The idea is, that his faith seemed to be all gone. He was like a falling man; a man who had no strength to walk.