Gift of the Holy Spirit
The gift of the Holy Spirit is the greatest gift God can give to man, for the Holy Spirit is a member of the triune Godhead. He brings with Him into human life all that is purely spiritual. When Adam sinned, the spirit part of man was extinguished. The human spirit had been indwelt by the Holy Spirit. But when Adam sinned the Holy Spirit departed, and the lamp went out. At the time of our conversion the Holy Spirit comes back to indwell the human spirit, and He relights the lamp. He Himself is the holy, fragrant oil that makes possible spiritual life for man.
John Phillips, Exploring Acts: An Expository Commentary, The John Phillips Commentary Series (Kregel Publications; WORDsearch Corp., 2009), Ac 8:20.