It is quite right that you should feel that “something terrific” has happened to you (It has) and be “all glowy.” Accept these sensations with thankfulness as birthday cards from God, but remember that they are only greetings, not the real gift. I mean, it is not the sensations that are the real thing. The real thing is the gift of the Holy Spirit which can’t usually be—perhaps not ever—experienced as a sensation or emotion. The sensations are merely the response of your nervous system. Don’t depend on them. Otherwise when they go and you are once more emotionally flat (as you certainly will be quite soon), you might think that the real thing had gone too. But it won’t. It will be there when you can’t feel it. May even be most operative when you can feel it least.
Lewis’ words are helpful because he distinguishes between the Holy Spirit and our feelings connected with God’s blessings. He is right in cautioning us not to confuse God’s gift of the Holy Spirit and our sensations when good things happen to us. Our good experiences of positive things are good but are temporary and fleeting. Our emotions ebb and flow with life events, but what remains constant is God’s faithfulness. In 1 John 3:18-20, the apostle John says,
“18 Little children, let us not love with word or with tongue, but in deed and truth. 19 We will know by this that we are of the truth, and will assure our heart before Him 20 in whatever our heart condemns us; for God is greater than our heart and knows all things.”
John is encouraging us to have an assurance based on the truth of God’s Word, the Good News of His Son, and His promises. Even if your hearts condemn, John tells you not to pay attention to your feelings, but instead let your hearts and consciences be formed by the truth of God’s work for you in Christ. God’s verdict of our justification through His Son, His calling us clean and good and righteous, is greater than what we feel, so let God’s Word have the final say.