John 13:23

There was at the table reclining in Jesus' bosom one of his disciples, whom Jesus loved. Simon Peter therefore beckoneth to him, and saith unto him, Tell us who it is of whom he speaketh.

At the table reclining ... According to the custom of the times, the guests surrounded the table, which was not an elevated platform at all, such as modern tables, but only a slightly elevated place, or only a covering placed on the floor. Each guest lay on his elbow, leaving one hand free for eating. In such a position, it was easy for one guest to whisper to another.

Whom Jesus loved ... This expression appears seven times in John, twice with reference to Lazarus and his sisters, and five times with reference to John himself. As Gaebelein said:

John has been charged with egotism in speaking thus of himself; but the charge is unfounded. He wrote under the guiding hand of the Holy Spirit who put these words in his pen.[6]

John had already stated in John 13:1 that the Lord loved all of his disciples "to the uttermost."

Simon Peter ... used some kind of body language in his request of John, "beckoning" to him to find out who Jesus meant. Whatever the gesture was, John understood it.