“Early in the morning,

Jesus came

Walking toward them,

On the sea.

But when the disciples saw him

Walking on the sea,

They were terrified.

They said.

‘It is a ghost!’

They cried out in fear!

But immediately,

Jesus spoke to them.

He said.

‘Have courage!

It is I!

Do not be afraid!’”

τετάρτῃ δὲ φυλακῇ τῆς νυκτὸς ἦλθεν πρὸς αὐτοὺς περιπατῶν ἐπὶ τὴν θάλασσαν.

οἱ δὲ μαθηταὶ ἰδόντες αὐτὸν ἐπὶ τῆς θαλάσσης περιπατοῦντα ἐταράχθησαν λέγοντες ὅτι Φάντασμά ἐστιν, καὶ ἀπὸ τοῦ φόβου ἔκραξαν.

εὐθὺς δὲ ἐλάλησεν ὁ Ἰησοῦς αὐτοῖς λέγων Θαρσεῖτε, ἐγώ εἰμι· μὴ φοβεῖσθε.

This incident about Jesus walking on water can be found in Mark, chapter 6:48-50, and John, chapter 6:19-20, but without some of the details here.  However, in all three stories, the disciples are afraid and the response of Jesus is the same.  Early in the morning or the 4^th watch of the night (τετάρτῃ δὲ φυλακῇ τῆς νυκτὸς), Jesus came walking towards them on the sea (ἦλθεν πρὸς αὐτοὺς περιπατῶν ἐπὶ τὴν θάλασσαν).  When the disciples saw him walking on the sea (οἱ δὲ μαθηταὶ ἰδόντες αὐτὸν ἐπὶ τῆς θαλάσσης περιπατοῦντα), they were terrified, troubled, or disturbed (ἐταράχθησαν).  They said that it was a ghost or an apparition (λέγοντες ὅτι Φάντασμά ἐστιν).  They cried out in fear (καὶ ἀπὸ τοῦ φόβου ἔκραξαν).  But immediately, Jesus reassured them (εὐθὺς δὲ ἐλάλησεν ὁ Ἰησοῦς αὐτοῖς).  He told them to have courage and take heart (λέγων Θαρσεῖτε).  He said that he was not a ghost but Jesus himself (ἐγώ εἰμι), so that they did not have to be afraid.  They had nothing to fear (μὴ φοβεῖσθε).  Jesus reassured his disciples, while he walked on the waters of the sea.