An excerpt from a booklet I'm working on about the feasts:
On Pentecost, Peter explained the outpouring of the Holy Spirit in this way: "God has raised this Jesus to life, and we are all witnesses of the fact. Exalted to the right hand of God, he has received from the Father the promised Holy Spirit and has poured out what you now see and hear" (Acts 2:32, 33). God anointed Jesus with the fullness of the Holy Spirit, choosing Him to be Christ (="Anointed One") (Acts 2:36). Christ's anointing then flowed down to the church, joining Christ and His people into one body through one Spirit.
Sharing in Christ’s anointing means several things. First John 2:20 says, “But you have an anointing from the Holy One, and all of you know the truth.” The Holy Spirit reminds us of everything Jesus said, testifies of Him, and leads us into all truth in Him (John 14:26, 15:26, 16:13-15). The Holy Spirit also supplies the capability and competence to minister and represent Christ in the ways He has called (2 Cor. 3:5, 6). Scripture mentions many abilities the Holy Spirit may give us. Speaking in tongues, writing songs or poetry, governing, metalsmithing, pastoring, interpreting dreams, giving to charity…there are, literally, as many spiritual skill sets as there are people (Ex. 31:1-5; Dan. 1:17; 1 Cor. 12:4-11, 28; Rom. 12:6-7).
As we give ourselves in the ways God has called us, it is vital to remember that the anointing is on Christ, not on us. We share in it simply because we are in Him (Eph. 1:13). Some conceive of the anointing as an almost temperamental, flighty presence: if we have spent enough time with God and are living up to His expectations, then He will anoint us. If we have failed in some way or if we aren’t at our spiritual peak (“prayed up” or “filled up”) because of some lack of discipline, then the anointing will leave us or not show up when we need it. But the anointing is on Christ, and, since we are in Christ, the anointing cannot be removed from us unless we can be removed from Christ. Anointing is every bit as unchanging in Christ as His blood and forgiveness. It is always available, not because we behave, but because we believe (Gal. 3:2). It isn’t recent sins, failure to pray enough, or lack of Bible study that affects the flow of God’s Spirit. It is the unbelief of meditating on these things that robs us of the anointing that is always ours in Christ. If we believe the truth, we believe that our union with Christ—and therefore with the anointing of His Spirit—never changes. Believing this, in turn, will improve our morals, our prayer life, and all the other things we try to maintain for fear of losing the anointing.