But immediately he spoke to them and said, “Take heart; it is I. Do not be afraid.” Mark 6:50
They thought they were seeing a ghost. After all, who walks on water? It must be a spirit, because certainly flesh and blood cannot walk upon the waves of a stormy sea, let alone upon the calm surface of a placid sea.
So Jesus identifies Himself to them. The translation given by the ESV and indeed by most English translations falls short of what Jesus is saying. The ESV translates Jesus saying, “Take heart; It is I. Do not be afraid.” William Weinrich states: “Again, it seems superficial to interpret Jesus’ words as a mere self-identification: “It is I, Jesus,” given the significance of these words in the OT…” [Jn, vol. 1, 654]. What words is Dr. Weinrich referencing? Jesus, while walking upon the water, said to the Apostles (literal translation): “Take heart; I AM. Do not be afraid.” Jesus is here identifying Himself as I AM: the God of the Old Testament. Moses replied to God at the burning bush: If I come to the people of Israel and say to them, ‘The God of your fathers has sent me to you,’ and they ask me, ‘What is his name?’ what shall I say to them?” God said to Moses, “I AM who I AM.” And he said, “Say this to the people of Israel: ‘I AM has sent me to you [Ex 3:13,14].’ The Greek translation of I AM in these Old Testament verses is precisely the Greek used by Jesus in our text. The Apostles should take heart and not be afraid, for Jesus is I AM, the eternal God who brought Israel out of slavery.
Many Christians have observed such a reference in John 8:58, where Jesus spoke to the Jews: Truly, Truly I say to you, before Abraham was, I AM. Most English translators get this right. Jesus is here clearly identifying Himself as the same I AM encountered by Moses. However, unbeknownst to many, the Greek New Testament reflects this I AM-identification of Jesus on numerous occasions. See e.g. John 4:26; 8:24, 25; 13:19; 18:5, 6,8. Though such “I AM” references are not as common outside of John’s Gospel, yet the parallel accounts of Jesus walking on the sea (our text; Matt 14:27; Jn 6:20) record Jesus identifying Himself as the I AM.
This then answers the question, Who walks on the water? It is God who walks upon the stormy sea; it is God who became a man for our salvation. This identification of God as the water-walker is made in the Old Testament: Your way was through the sea, your path through the great waters; yet your footprints were unknown [Psalm 77:19]. Perhaps it is even clearer in Job 9:8:…who alone stretched out the heavens and trampled the waves of the sea (LXX translation: …walks on the sea as on firm ground).