A.T. Robertson Commentary Mark 3:21

"And when his friends heard it, they went out to lay hold on him: for they said, He is beside himself." — Mark 3:21 (ASV)

His friends (ο παρ' αυτου). The phrase means literally "those from the side of him (Jesus)." It could mean another circle of disciples who had just arrived and who knew of the crowds and strain of the Galilean ministry who now come at this special juncture. But the idiom most likely means the kinspeople or family of Jesus as is common in the LXX. The fact that in verse 31 "his mother and his brothers" are expressly mentioned would indicate that they are "the friends" alluded to in verse 21. It is a mournful spectacle to think of the mother and brothers saying,

He is beside himself (εξεστη). Second aorist active indicative intransitive. The same charge was brought against Paul (Acts 26:24; 2 Corinthians 5:13). We say that one is out of his head. Certainly Mary did not believe that Jesus was in the power of Beelzebub as the rabbis said already. The scribes from Jerusalem are trying to discount the power and prestige of Jesus (3:22). See on Mt 9:32-34; 10:25; 12:24 for Beelzebub and Beelzebul. Mary probably felt that Jesus was overwrought and wished to take him home out of the excitement and strain that he might get rest and proper food. See my The Mother of Jesus: Her Problems and Her Glory. The brothers did not as yet believe the pretensions and claims of Jesus (John 7:5). Herod Antipas will later consider Jesus as John the Baptist redivivus, the scribes treat him as under demonic possession, even the family and friends fear a disordered mind as a result of overstrain. It was a crucial moment for Jesus. His family or friends came to take him home, to lay hold of him (κρατησα), forcibly if need be.