In our fleshly nature, all of us have certain weaknesses. These weaknesses are not of the body but of the mind—of our understanding. They manifest themselves in two related ways. First, we often do not know what we should pray for. Second, even when we do know what to pray for, we do not know how to pray for it. We are therefore shut up to total dependence on the Holy Spirit. He alone can show us both the what and the how of prayer. (See Romans 8:26–27.)
In the book of Ephesians, Paul emphasized our dependence upon the Holy Spirit to give us prayers that are acceptable to God. He stressed that it is only Jesus and the Holy Spirit who can give us access to God:
For through Him [Jesus Christ] we both [Jews and Gentiles] have access by one Spirit [the Holy Spirit] to the Father. (Ephesians 2:18)
Two conditions for acceptable prayers are here combined: through Jesus and by the Holy Spirit. Each is essential. There is no natural force that can carry our puny human voices from earth to the very ears of God on His throne in heaven. Only the supernatural power of the Holy Spirit can do that. Without Him, we have no access to God.