“And when his friends heard of it, they went out to lay hold on him: for they said, He is beside himself.”
When his family heard about this, they went to take charge of him, for they said, he is out of his mind — the family's assessment — he is out of his mind (existē, he has lost his senses) — is Mark's most startling detail in the early chapters. Jesus' own family interprets the intensity of his ministry as evidence of mental instability. The took charge of him (kratēsai, to seize, to take hold of) communicates that they intend to physically intervene and remove him. The family's response is not hostile but concerned — they are acting from love, not malice. But their love is uninformed about who Jesus is and what the kingdom requires of him.
Church Fathers on Mark 3:21
the Lord leads the Apostles, when they were elected, into a house, as if admonishing them, that after having received the Apostleship, they should retire to look on their own consciences.
That is, He has a devil and is mad, and therefore they wished to lay hold upon Him, that they might shut Him up as one who had a devil. And even His friends wished to do this, that is, His relations, perchance His countrymen, or His brethren. But it was a silly insanity in them, to conceive that the Worker of such great miracles of Divine Wisdom had become mad.
But mystically, the house to which they came, is the early Church. The crowds which prevent their eating bread are sins and vices; for he who eateth unworthily, 'eateth and drinketh damnation to himself.' [1 Cor 11:29]