Holy spirit is his power. Is that so hard to understand?
John 14:16 I will ask the Father and he will give you another helper to be with you forever, 17 the spirit of the truth, which the world cannot receive, because it neither sees it nor knows it. You know it, because it remains with you and is in you.
John 14:26 But the helper, the holy spirit, which the Father will send in my name, that one will teach you all things and bring back to your minds all the things I told you.
1 Corinthians 2:12 Now we received, not the spirit of the world, but the spirit that is from God, so that we might know the things that have been kindly given us by God.
John 16:7 Nevertheless, I am telling you the truth, it is for your benefit that I am going away.
For if I do not go away, the helper will not come to you; but if I do go, I will send him to you. 8 And when that one comes, he will give the world convincing evidence concerning sin and concerning righteousness and concerning judgment:
John 16:13 However, when that one comes, the spirit of the truth, he will guide you into all the truth, for he will not speak of his own initiative, but what he hears he will speak, and he will declare to you the things to come.
According to John 16:7 Jesus will send God's power to be their helper.