The Holy Spirit is inside us to help us in our weaknesses. Where we are without strength, He is there to help us. When we don’t know what to pray, “the Spirit Himself makes intercession for us with groanings which cannot be uttered”. Romans 8:26
If you don’t pray and just sit back and don’t take hold of the problem, the Holy Spirit has nothing to “take hold of” with you. He has nothing to pray. If you keep quiet, then even if He wants to pray through you, He can’t.
You can rest assured that when you ask anything according to the will of God, He hears you. And if you know that He hears you, whatever you ask, you know that you have the petitions that you have asked of Him! (1 John 5:14–15)