It is well that you bring this matter before the throne of grace, for the sword of prayer has such an edge that it will cut through coats of mail. When a soul is shut up within prison walls, the reasons may be hidden from our eyes, yet the Lord who hears and answers prayer knows all unknown depths. Man remains a mystery even to himself, and the heart of your friend is an unread page to you at this hour. Whether the cause be sin or slander, folly or false accusation, cast this weight upon Him who knows what is in man.
Yet take heed that your prayer be mingled with humility, which is the fit attitude of all supplication. Do not approach the mercy seat with a proud list of demands, but go as a sinner pleading for a sinner. Remember that the Friend of sinners is Jesus Christ Himself, a friend that loves at all times, a friend that sticketh closer than a brother. Behold how He prayed even for those who pierced His hands, crying, "Father, forgive them; for they know not what they do." Here are unknown heights of mercy, and you may plead Christ's own heart for your imprisoned friend.
While you know not the reason, use this very ignorance as an argument in prayer. Spread the case before your Lord, and ask that whatever the hidden cause may be, it might work for eternal good. The hand of the law may have seized your friend, but the pierced hand of the sinner's Friend can unlock gates of iron and bars of brass. Pray that this confinement would become the birthplace of true liberty, even that liberty wherewith Christ makes men free.
But I must ask a searching question, is Jesus Christ the friend of the one for whom you pray? If he remains unrepentant, his very prayer would be an abomination to God, for God hears not sinners in their rebellion. Yet there is hope, for Christ came to seek and save such. Plead with the Master that this prison cell might become a sanctuary of conviction and conversion. You have found Jesus to be a true Brother and a blessed Friend; now let the same be true of you, prove yourself a faithful intercessor, forsaking not your own friend and your father's Friend.
Your prayer shall be answered, but perchance not in the way you expect. The Lord may grant release, or He may give patience and peace within the walls. The answer might come as the opening of a prison door, or as the opening of a blind heart. Hannah prayed for a child and received not only a son, but a prophet. Wait upon God, who is rich in mercy, and expect great things from the hand that was nailed for sinners. Prayer and praise together make up our spiritual breath; breathe in the air of heaven now, and soon you shall breathe out a song of deliverance.