John Gill Commentary Matthew 14:30

"But when he saw the wind, he was afraid; and beginning to sink, he cried out, saying, Lord, save me." — Matthew 14:30 (ASV)

But when he saw the wind boisterous
Or "strong", blowing hard against him, and raising up the waves, which beat with great violence upon him,

he was afraid ;
though Christ was so nigh him, and he had had such an instance of his power in bearing him up, causing him to walk upon the waters thus far; which shows, that his faith was imperfect:

and beginning to sink ;
through fear, and the violence of the wind and waves, just ready to be immersed, and go down to the bottom of the sea,

he cried ;
being in a great fright and much danger, and with great importunity and eagerness,

saying, Lord, save me :
I am just going, I shall certainly perish else; still having so much faith in Christ, that he was able to save him in the last extremity.