Relating to God with our heart and devotion is holy prayer. We should often praise, thank, repent and intercede the best we can. The virtues we receive from the Lord–faith, hope, charity (love) will guide this communication with God. And the Holy Spirit will be involved if we are open to His guidance.
After we pray the best we can as Christians, we pray in tongues and let the Spirit Himself praise, thank and intercede on our behalf. On the natural level our communication in an unknown language is meaningless; this meaningless language is a sacramental that reminds us of our littleness and our reliance on a Divine Person. On the supernatural level we are relying on an understanding and love that is greater than ours. We are being humble and surrender to the Holy Spirit Himself. This reliance is indispensable for growth in holiness.
If the Spirit intercedes for the saints according to the will of God, that prayer will have results, whether evident to us or hidden.
Holiness requires us to identify with the Holy Spirit in all our activities. As we begin some task or service or ministry, we rightly pray in tongues to identify with the Person and presence of the Holy Spirit, to submit to His guidance and His power. Then He receives all the Glory!
When we pray in tongues to the Father, we let the Spirit pray His perfect but mysterious and secret prayer on our behalf.
“But you, beloved, build yourselves up on your most holy faith; pray in the Holy Spirit.”
— NABRE, 2011, Jude verse 20
“In the same way, the Spirit too comes to the aid of our weakness; for we do not know how to pray as we ought, but the Spirit itself intercedes with inexpressible groanings. And the one who searches hearts knows what is the intention of the Spirit, because it intercedes for the holy ones according to God’s will.”
— NABRE, 2011, Romans 8:26–27
“For one who speaks [prays] in a tongue speaks not to men but to God; for no one understands him, but he utters mysteries in the Spirit. . . . He who speaks (prays) in a tongue edifies himself, but he who prophesies edifies the church. Now I want you all to speak (pray) in tongues, but even more to prophesy.”
— NABRE, 2011, 1 Corinthians 14:2–5
Praying in tongues edifies and strengthens our holy faith, our reliance on the Holy Spirit!