Faith

Then He (Jesus) directed the disciples to get into the boat and go before Him to the other side, while He sent away the crowds.  And after He had dismissed the multitudes, He went up into the hills by Himself to pray. When it was evening, He was still there alone.

But the boat was by this time out on the sea, many furlongs [a furlong is one-eighth of a mile] distant from the land, beaten and tossed by the waves, for the wind was against them. And in the fourth watch [between 3:00--6:00 a.m.] of the night, Jesus came to them, walking on the sea.

And when the disciples saw Him walking on the sea, they were terrified and said, It is a ghost! And they screamed out with fright.  But instantly He spoke to them, saying, Take courage! I AM! Stop being afraid.

28And Peter answered Him, Lord, if it is You, command me to come to You on the water. He said, Come! So Peter got out of the boat and walked on the water, and he came toward Jesus.  But when he perceived and felt the strong wind, he was frightened, and as he began to sink, he cried out, Lord, save me [from death]!

Instantly Jesus reached out

His hand and caught and held him, saying to him, O you of little faith, why did you doubt?  And when they got into the boat, the wind ceased.  And those in the boat knelt and worshiped Him, saying, Truly You are the Son of God! (Matthew 14:22-33 AMP)

 1John 4:16