A.T. Robertson Commentary John 5:21

"For as the Father raiseth the dead and giveth them life, even so the Son also giveth life to whom he will." — John 5:21 (ASV)

Quickeneth whom he will (ους θελε ζωοποιε). Present active indicative of ζωοποιεω (from ζωοποιος, making alive), common in Paul (1 Corinthians 15:45, etc.). As yet, so far as we know, Jesus had not raised the dead, but he claims the power to do it on a par with the power of the Father. The raising of the son of the widow of Nain (Luke 7:11–17) is not far ahead, followed by the message to the Baptist which speaks of this same power (Luke 7:22; Matthew 11:5), and the raising of Jairus' daughter (Matthew 9:18,22-26). Jesus exercises this power on those "whom he wills." Christ has power to quicken both body and soul.