"For through Him we both have access by one Spirit unto the Father" (Ephesians 2:18).
We cannot see or hear the Holy Spirit, but He is very real and is, in fact, the very life of each true Christian. It is only through Him that we have access in prayer to the Father, as our text points out. Christ in His resurrection body is seated at the right hand of the Father in the distant heavens, but the Holy Spirit has His temple in our very bodies.
He not only hears each spoken prayer, but also each thought of our hearts. From the moment we receive Christ, we live in the Spirit; He is always with us, to guide our steps, to bear witness with our spirits that we belong to God, to illumine our understanding and, when needed, to convict and chasten when we get out of His will.
Therefore, "If we live in the Spirit, let us also walk in the Spirit" (Galatians 5:25). When we yield to some worldly temptation, it is because we have ignored this admonition for the promise is "Walk in the Spirit, and ye shall not fulfill the lust of the flesh" (Galatians 5:16). The very presence of the Holy Spirit assures our eternal salvation, so how can we ignore His holy constraints on our behavior? "Grieve not the holy Spirit of God, whereby ye are sealed unto the day of redemption" (Ephesians 4:30). We speak of worshiping God in church, or home, or elsewhere, but if we really worship Him, we must "worship God in the spirit" (Philippians 3:3), for we have access to the Father, and the Son, only in the Spirit.
When we pray, we must be "Praying always with all prayer and supplication in the Spirit" (Ephesians 6:18). "Ye are not in the flesh, but in the Spirit, if so be that the Spirit of God dwell in you. Now if any man have not the Spirit of Christ, he is none of His. . . . For as many as are led by the Spirit of God, they are the sons of God" (Romans 8:9,14). HMM