20 Peter turned and saw the disciple whom Jesus loved following them. He was the one who had leaned back against Jesus at the supper to ask, “Lord, who is going to betray You?”
John 21:20 Cross References - MSB
John 13:23-26
23 One of His disciples, the one whom Jesus loved, was reclining at His side.
24 So Simon Peter motioned to him to ask Jesus which one He was talking about.
25 Leaning back against Jesus, he asked, “Lord, who is it?”
26 Jesus answered, “It is the one to whom I give this morsel after I have dipped it.” Then He dipped the morsel and gave it to Judas Iscariot, the son of Simon.
John 20:2
2 So she came running to Simon Peter and the other disciple, the one whom Jesus loved. “They have taken the Lord out of the tomb,” she said, “and we do not know where they have put Him!”
John 21:7
7 Then the disciple whom Jesus loved said to Peter, “It is the Lord!” As soon as Simon Peter heard that it was the Lord, he put on his outer garment (for he had removed it) and jumped into the sea.
John 21:24
24 This is the disciple who testifies to these things and who has written them down. And we know that his testimony is true.