Matthew 14:31 - Coke's Commentary on the Holy Bible

Jesus stretched forth his hand, &c.— Peter did not doubt that it was Jesus who walked upon the water; he might have been convinced of that, as we observed in the former note, before he left the vessel; nay, must have been convinced of it while he was sinking, otherwise he would not have called to him for assistance; but he was afraid that Jesus could not or would not support him against the wind, which blew more fiercely than before: a doubt most unreasonable and culpable, since it was as easy to support him against the storm, as to keep him above the water, which Jesus had virtually promised todo by his permission, and which he had actually performed, when Peter first left the vessel. See the Inferences.