The spirit of a man is the lamp of the Lord, searching all the inner depths of his heart. Proverbs 10:27
God never changes His mind concerning you. Through some act of sin you may grieve His Spirit, but once you are saved, God will not take His presence from you.
In his book, The Person and Work of the Holy Spirit, R. A. Torrey asserts,
In some, however, He dwells way back of consciousness in the hidden sanctuary of their spirit. He is not allowed to take possession as He desires of the whole man, spirit, soul, and body. Some therefore are not distinctly conscious of His indwelling, but He is there nonetheless. What a solemn, and yet what a glorious thought, that in me dwells this august person, the Holy Spirit.
If we are children of God, we are not so much to pray that the Spirit may come and dwell in us, for He does that already. We are rather to recognize His presence, His gracious and glorious indwelling, and give to Him complete control of the house He already inhabits, and strive so to live as not to grieve this holy one, this divine guest . . .
What a thought it gives of the hallowedness and sacredness of the body, to think of the Holy Spirit dwelling within us. How considerately we ought to treat these bodies and how sensitively we ought to shun every thing that will defile them. How carefully we ought to walk in all things so as not to grieve Him who dwells within us.
Father, let me be sensitive to things that would defile me. I want to be Your holy temple.