In him you also, when you heard the word of truth, the gospel of your salvation and believed in him, were sealed with the promised Holy Spirit, who is the guarantee of our inheritance until we acquire possession of it. Ephesians 1:13-14
In four places (2 Cor 1:22; 5:5; Eph 1:13-14; 4:30) the Apostle Paul speaks of the gift of the Holy Spirit as the seal of our salvation. In another (Rom 8:16) he speaks of him as witnessing to us that we are indeed children of God.
What is Paul saying to us? He is saying that salvation is not simply a legal transaction, something that changes our status on paper. Rather, it is a move into a whole new relationship. This was a very important issue for John Wesley. Had he repented, believed, and accepted Christ as his Savior long before May 28, 1738? Certainly he had. I have no doubt that had he died before that day, God would have welcomed him home. But what he did not have was the witness of the Spirit that Christ had died for him. That is what was given him that night on Aldersgate Street. And with that assurance ringing in his heart, he and his brother Charles went out to change the face of England.
The Holy Spirit, producing his fruit within us, is God’s down payment on our final glorification. It says that we belong to God, having his seal upon us as evidence that we are his and belong to him. To be a Christian is to share the life of Christ in a living relationship with him. Is there typically some later moment when we allow the Holy Spirit to take all of us? Yes, but that is only the full development of that relationship with the Spirit that is intended to characterize the beginning of our walk with him. So the witness of the Spirit is your birthright. Are you, like Wesley was, claiming salvation on the basis of your having met the requirements? Oh, there is so much more! Ask God to give you the witness of his Spirit that he is yours and you are his.