There is the statement that the prayerless Christian is the powerless Christian. Although prayer is not the only thing that keeps the Christian growing but it cannot be neglected. Like Bible reading and doing good works, prayer is needed and here John Bunyan who authored Pilgrim's Progress says, "The truths that I know best I have learned on my knees. I never know a thing well, till it is burned into my heart by prayer."
The classic Christian truth on the prayer life is that prayer does not change God, it changes the Christian who prays. When a Christian prays, it is never for personal glory but to seek God who will be glorified. As the Lord's prayer says these words, "Hallowed be Thy name, Thy Kingdom come, Thy will be done on Earth as it is in Heaven." When Jesus prayed in the Garden of Gethshemene, he said, "Not My will but Thine."
The classic example of learning through prayer would be Solomon. The prayer can be remembered as follows as 1 Kings 3:6-9 says, "And Solomon said, Thou hast shewed unto thy servant David my father great mercy, according as he walked before thee in truth, and in righteousness, and in uprightness of heart with thee; and thou hast kept for him this great kindness, that thou hast given him a son to sit on his throne, as it is this day. And now, O Lord my God, thou hast made thy servant king instead of David my father: and I am but a little child: I know not how to go out or come in. And thy servant is in the midst of thy people which thou hast chosen, a great people, that cannot be numbered nor counted for multitude. Give therefore thy servant an understanding heart to judge thy people, that I may discern between good and bad: for who is able to judge this thy so great a people?"
Looking at the prayer of Solomon, as long as he remained in faithful prayer, he did not backslide. It was only when he started to go astray from God that he backslid and compromised with the heathen women he had a political marriage with. Only later was Solomon restored during his repentance which can be read in the Book of Ecclesiastes, he was the King of Israel who had revealed how much his own life had been a waste and he repented of it.
If kings were not the only ones who learned through prayer, it was also the prophets. Elijah learned through prayer in his battle against the wickedness of Ahab and Jezebel. Every prophet always got to their knees to pray for guidance because they know that they must speak God's Word with so much caution. They had to ask God for wisdom before they did anything because a prophet of God was an outcast of a society that's so drowned in sin. They needed guidance in moving in the midst among wolves.
The Christian likewise is told by the Apostle Paul in 1 Thessalonians 5:17 saying, "Pray without ceasing." While it seems to say that one has to be on their knees 24/7 but that is not what it meant. A more accurate translation is, "Pray continually." Got Questions says this on "What does it mean to pray without ceasing?":
When our thoughts turn to worry, fear, discouragement, and anger, we are to consciously and quickly turn every thought into prayer and every prayer into thanksgiving. In his letter to the Philippians, Paul commands us to stop being anxious and instead, “in everything, by prayer and petition, with thanksgiving, present your requests to God” (Philippians 4:6). He taught the believers at Colossae to devote themselves “to prayer, being watchful and thankful” (Colossians 4:2). Paul exhorted the Ephesian believers to see prayer as a weapon to use in fighting spiritual battles (Ephesians 6:18). As we go through the day, prayer should be our first response to every fearful situation, every anxious thought, and every undesired task that God commands. A lack of prayer will cause us to depend on ourselves instead of depending on God's grace. Unceasing prayer is, in essence, continual dependence upon and communion with the Father.
For Christians, prayer should be like breathing. You do not have to think to breathe because the atmosphere exerts pressure on your lungs and essentially forces you to breathe. That is why it is more difficult to hold your breath than it is to breathe. Similarly, when we are born into the family of God, we enter into a spiritual atmosphere where God's presence and grace exert pressure, or influence, on our lives. Prayer is the normal response to that pressure. As believers, we have all entered the divine atmosphere to breathe the air of prayer.