Perhaps the only really difficult phrase of this verse to understand is that line “according to the spirit of holiness.”  Theologians and commentators debate over whether this refers to the Holy Spirit of God, the third person of the sacred Trinity, or to the human spirit of Christ, which was completely holy, utterly unspoiled by sin.  Without venturing into any deep waters, or weighing any arguments, I will simply say that I prefer to believe the apostle has reference to the Holy Spirit of God, Who played an active part in the resurrection of Christ, and was strongly involved in declaring Him to be the Son of God with power.  Not only did the Spirit of God actively participate in raising Christ from the dead, He empowered the apostles, who went forth throughout the known world proclaiming the message of the resurrection, and the divine sonship of the Lord Jesus.

Perhaps one reasonable objection to this position would be that, if we assume the “spirit of holiness” in verse 4 to be the Holy Spirit, then there could be a debate over whether the “Whom” of verse 5 would be the Holy Spirit or Christ Himself.  This would be an argument of no great weight, because the Godhead certainly worked in unison in empowering and equipping the apostles for the mighty work of proclaiming the Gospel to the nations.  However, even considering the position I took on “the spirit of holiness,” I rather believe the “Whom” of verse 5 is the same glorious Person Who is the subject and the heart of the message that Paul preached: Jesus Christ our Lord, Who was made of the seed of David according to the flesh, and yet at the same time is the Son of God with power.  It is He Who personally summoned and appointed each one of His apostles, sent His Spirit to bestow upon them all necessary graces for the monumental task they must perform, and sustained them to the very end.  Christ’s purpose in appointing these men and then sending them forth as sheep in the midst of wolves to preach His name, was that His elect people from among the nations would obey the faith of Christ and be saved.