But when he saw the wind boysterous ( ἰσχυρόν is clearly a gloss, and therefore omitted by the Revised Version). He was afraid; and beginning to sink. The natural tendency to sink, which he had had all the time, was counteracted before by his faith, which enabled him to receive Christ's power.
But now that his doubt made him incapable of receiving this, he sank (cf. Meyer). He cried ( ἔκραξεν), saying, Lord, save me (Matthew 8:25). Aphraates quotes an apocryphal saying of our Lord's, "Doubt not; lest ye are engulfed in the world, as Simon; for he doubled, and began to sink in the sea."