20 Then Peter, turning about, saw the disciple whom Jesus loved following; who also leaned on his breast at supper, and said, Lord, who is he that betrays you?
John 21:20 Cross References - KJ2000
John 13:23-26
23 Now there was leaning on Jesus' bosom one of his disciples, whom Jesus loved.
24 Simon Peter therefore beckoned to him, that he should ask who it should be of whom he spoke.
25 He then lying on Jesus' breast said unto him, Lord, who is it?
26 Jesus answered, He it is, to whom I shall give a morsel, when I have dipped it. And when he had dipped the morsel, he gave it to Judas Iscariot, the son of Simon.
John 20:2
2 Then she ran, and came to Simon Peter, and to the other disciple, whom Jesus loved, and said unto them, They have taken away the Lord out of the sepulcher, and we know not where they have laid him.
John 21:7
7 Therefore that disciple whom Jesus loved said unto Peter, It is the Lord. Now when Simon Peter heard that it was the Lord, he girded his fisher's coat unto him, (for he was naked,) and did cast himself into the sea.
John 21:24
24 This is the disciple who testifies of these things, and wrote these things: and we know that his testimony is true.