There came then his brethren and his mother
 At the same time he was speaking to the Scribes, who seem to be different persons from his friends and kinsmen, ( Mark 3:21 ) , 
 and standing without;
 for Christ was within, in the house, talking with the Scribes and Pharisees, and preaching to the people; and the crowd being so great, that they could not get into the house; they 
 sent unto him, calling him:
 they not only sent one in to let him know who they were, and that they were without doors, desirous to speak with him; but also, with a voice as loud as they could, called to him themselves; (See Gill on Matthew 12:46).