Who is the "He" who raised Christ from the dead in Ephesians 1:20?

The “He” is God the Father, the one Paul addresses in Ephesians 1:17. The context identifies Him as the source of resurrection power who raised Christ from the dead. It also presents this action as involving the triune God—Father and Spirit—setting Christ at His own right hand.

Les explains that the pronoun usage in Ephesians 1:20 points back to God the Father, mentioned in verse 17. The verse says the power was wrought in Christ when He raised Him from the dead. Les identifies this as God the Father, and God the Spirit, and again the triune God, raising Christ and setting Him at His own right hand in the heavenlies. He emphasizes it was done by an outside personage, for Jesus did not set Himself down. Les also stresses that resurrection is the epitome and high point of everything God accomplished; if there is no resurrection, everything else falls apart.

Ephesians 1:20

Which he wrought in Christ, when he raised him from the dead, and set him at his own right hand in the heavenly places,

Ephesians 1:17

That the God of our Lord Jesus Christ, the Father of glory, may give unto you the spirit of wisdom and revelation in the knowledge of him:

How does Les describe the power God worked in Christ when He raised Him from the dead?

This tremendous, all-consuming power is the resurrection power God wrought in Christ when He raised Him from the dead. Resurrection is the epitome, the high point of everything God has accomplished, and without it everything else falls apart. It is the power that raised Christ and set Him at God's right hand in the heavenlies.