Mark says it at the outset of his gospel (1:1).

The angel told Mary her child would be the Son of God (Luke 1:35).

John the Baptist said the same thing (John 1:34).

Nathanael said it (John 1:49).

Martha believed it (John 11:27).

The centurion said so (Matthew 27:54).

Jesus claimed that He said so (John 10:36).

Jesus clearly implies it in John 11:4.

The demons called Jesus the Son of God (Matthew 8:29; Luke 4:41; Mark 3:11).

The charge against Jesus was that He claimed to be the Son of God (Matthew 27:43; John 19:7), a claim He never denied, and virtually admitted (Luke 22:70).

The Gospel of John was written to convince the reader that Jesus was the Son of God (John 20:31).

Why, you might ask, does Jesus not say so plainly. I think the answer is found in Matthew 16:15-17:

15 He said to them, “And who do you say that I am?” 16 Simon Peter answered, “You are the Christ, the Son of the living God.” 17 And Jesus answered him, “You are blessed, Simon son of Jonah, because flesh and blood did not reveal this to you, but my Father in heaven!” (Matthew 16:15-17).

Jesus did not want Peter and His disciples to believe He was the Son of God just because He said so. He wanted God to bring them to this conclusion, based upon the overwhelming evidence of Scripture and our Lord’s life and teaching.