The three words, "It is I," are in Greek only two words (ego eimi), and they are much more powerful and significant than most Bible readers realize. Jesus says not, "It is I" but "I am," which is a direct assertion of His deity. Moses had asked God:
"Indeed, when I come to the children of Israel and say to them, 'The God of your fathers has sent me to you,' and they say to me, 'What is His name?' what shall I say to them?" And God said to Moses, "I AM WHO I AM." And He said, "Thus you shall say to the children of Israel, 'I AM has sent me to you.'" (Exodus 3:13-14).
Clearly, Jesus is declaring that He is the Yahweh of the Old Testament. Throughout the New Testament, there are a number of significant amplifications of this: Christ is the "I AM" that is the bread of life; the light of the world; the good shepherd; the resurrection; the way, the truth, and the life; and the Alpha and Omega, among other things (John 6:35; 8:12; 10:11; 11:25; 14:6; Revelation 1:8).
In the Garden of Gethsemane the night before the crucifixion, the "I AM" lesson was made unambiguous. When soldiers came to arrest Christ,
He went forward and said to them, "Whom are you seeking?" They answered Him, "Jesus of Nazareth." Jesus said to them, "I am He" ["He" has been inserted by the translators]. And Judas, who betrayed Him, also stood with them. Now when He said to them, "I am He," they drew back and fell to the ground. (John 18:4-6)
The disciples in their peril at sea needed the great "I AM." These two words alone should have removed all their fear.
In this incident, the disciples show that they were growing in faith. In the earlier miracle of Christ stilling the storm on the sea, they asked, "Who can this be, that even the winds and the sea obey Him?" (Matthew 8:27). Now they have advanced in their knowledge to recognizing Jesus as God (as "Son of God" indicates) and worshipping Him.
Recognizing that Jesus is God means that their worship was correct doctrinally. True worship cannot be separate from true doctrine. Jesus says to the woman at the well, "You worship what you do not know" (John 4:22). He could say this to some even in the greater churches of God today who sadly do not know enough about the Father and Christ. We, too, must know Him as the Son of God and fully divine to worship Him acceptably.
Martin G. Collins
The Miracles of Jesus Christ: Walking on the Water (Part One)