In order to bring many sons unto glory, Christ assumes to them the relation of brother.
He that sanctifieth (ὁ ἁγιάζων)
Sanctification is the path to glorification. Comp. Heb 10:14.
Of one (ἐξ ἑνὸς)
Probably God, although the phrase may signify of one piece, or of one whole. Jesus and his people alike have God for their father. Therefore they are brethren, and Christ, notwithstanding his superior dignity, is not ashamed to call them by that name.