Romans 8:26
And in the same way, the Holy Spirit helps [us in] our weakness; for we do not know what we ought to pray for [Note: Some translators understand this as "how to pray"]. But the Holy Spirit goes to God on our behalf with groanings [in our hearts] that are not expressed [in words].
1 Peter 3:12
For the Lord's eyes see what the righteous person does and He hears their [earnest] prayers, but the Lord looks with disapproval on the person who does wrong."
1 John 5:14-15
And this is [how we can express] boldness in our relationship with God: Whatever we ask [of God, in prayer], so long as it is in harmony with His will for us, [we know] He hears our request.