Question: God is holy and dwells apart from man in a holy place. How, then, can the Holy Spirit ...

Question: God is holy and dwells apart from man in a holy place. How, then, can the Holy Spirit indwell the human heart? My heart is not pure; I am a believer and serve the Lord Jesus Christ, but I am still a sinner. I am not holy. Only God is.

Response: Certainly God is holy, but according to Jesus, “If a man love me, he will keep my words: and my Father will love him, and we will come unto him, and make our abode with him” (Jn:14:23Jesus answered and said unto him, If a man love me, he will keep my words: and my Father will love him, and we will come unto him, and make our abode with him.
See All...). Jesus, as our great High Priest, was “holy, harmless, undefiled, separate from sinners, and made higher than the heavens” (Heb:7:26For such an high priest became us, who is holy, harmless, undefiled, separate from sinners, and made higher than the heavens;
See All...), yet God “was made flesh, and dwelt among us” (John:1:14And the Word was made flesh, and dwelt among us, (and we beheld his glory, the glory as of the only begotten of the Father,) full of grace and truth.
See All...). God dwells among men. He says so.

You ask how the Holy Spirit may indwell a human heart. When Jesus began preparing His apostles prior to His death on the Cross and subsequent departure from them, He said, “I will pray the Father, and he shall give you another Comforter, that he may abide with you for ever” (Jn:14:16And I will pray the Father, and he shall give you another Comforter, that he may abide with you for ever;
See All...). Where will He abide? According to 2 Corinthians:1:22Who hath also sealed us, and given the earnest of the Spirit in our hearts.
See All..., God “hath also sealed us, and given the earnest of the Spirit in our hearts.” That is His promise to every believer.

Our Lord came and lived in the “midst of a crooked and perverse nation” (Phil:2:15That ye may be blameless and harmless, the sons of God, without rebuke, in the midst of a crooked and perverse nation, among whom ye shine as lights in the world;
See All...) and did so without sin (Heb:4:15For we have not an high priest which cannot be touched with the feeling of our infirmities; but was in all points tempted like as we are, yet without sin.
See All...; 1 Pt 2:22). Remember, He was “holy, harmless, undefiled...” (Heb:7:26For such an high priest became us, who is holy, harmless, undefiled, separate from sinners, and made higher than the heavens;
See All...), yet that same Jesus in Revelation:3:20Behold, I stand at the door, and knock: if any man hear my voice, and open the door, I will come in to him, and will sup with him, and he with me.
See All... said clearly that “Behold, I stand at the door, and knock: if any man hear my voice, and open the door, I will come in to him, and will sup with him, and he with me.” Paul preached to the unsaved men on Mars Hill and told them plainly, “He be not far from every one of us” (Acts:17:27That they should seek the Lord, if haply they might feel after him, and find him, though he be not far from every one of us:
See All...).

You say your heart is not pure, yet Scripture promises, “If any man be in Christ, he is a new creature: old things are passed away; behold, all things are become new” (2 Cor:5:17Therefore if any man be in Christ, he is a new creature: old things are passed away; behold, all things are become new.
See All...). There is a solution for the believer who sins: “If we confess our sins, he is faithful and just to forgive us our sins, and to cleanse us from all unrighteousness” (1 Jn:1:9If we confess our sins, he is faithful and just to forgive us our sins, and to cleanse us from all unrighteousness.
See All...). If you are “a believer,” do you believe that we are holy, cleansed, and made perfect in God’s sight? Does He “cleanse us from all unrighteousness?”

Yes, there is a struggle, as old habits die hard. But remember the promise of Scripture: “For whom he did foreknow, he also did predestinate to be conformed to the image of his Son” (Romans:8:29For whom he did foreknow, he also did predestinate to be conformed to the image of his Son, that he might be the firstborn among many brethren.
See All...). Ephesians:2:10For we are his workmanship, created in Christ Jesus unto good works, which God hath before ordained that we should walk in them.
See All... tells us, “For we are his workmanship, created in Christ Jesus unto good works, which God hath before ordained that we should walk in them.” (See also Rom:12:1-2 [1] I beseech you therefore, brethren, by the mercies of God, that ye present your bodies a living sacrifice, holy, acceptable unto God, which is your reasonable service. [2] And be not conformed to this world: but be ye transformed by the renewing of your mind, that ye may prove what is that good, and acceptable, and perfect, will of God.
See All...; 1 Pt 1:13-16)

John explained that “if we walk in the light, as he is in the light, we have fellowship one with another, and the blood of Jesus Christ his Son cleanseth us from all sin” (1 Jn:1:7But if we walk in the light, as he is in the light, we have fellowship one with another, and the blood of Jesus Christ his Son cleanseth us from all sin.
See All...).

Paul encouraged the Corinthians, “For the love of Christ constraineth us; because we thus judge, that if one died for all, then were all dead: And that he died for all, that they which live should not henceforth live unto themselves, but unto him which died for them, and rose again” (2 Cor:5:14-15 [14] For the love of Christ constraineth us; because we thus judge, that if one died for all, then were all dead: [15] And that he died for all, that they which live should not henceforth live unto themselves, but unto him which died for them, and rose again.
See All...).

The Holy Spirit indwells the human heart because of the finished work of Christ, not by our merit. It is He who “purifies” our hearts. Ephesians:2:13But now in Christ Jesus ye who sometimes were far off are made nigh by the blood of Christ.
See All... tells us, “But now in Christ Jesus ye who sometimes were far off are made nigh by the blood of Christ.” And it is only through His blood that this is possible.