God ALWAYS listens to SINCERE prayers: "So Jehoahaz pleaded with the Lord, and the Lord listened to him; for He saw the oppression of Israel, because the king of Syria oppressed them. Then the Lord gave Israel a deliverer, so that they escaped from under the hand of the Syrians; and the children of Israel dwelt in their tents as before." (2 Kings 13:4-5)
Jehoahaz became king over Israel in Samaria and ruled for seventeen years during which time he did evil in the sight of Jehovah, and continued all the wrongful religious institutions of Jeroboam in making Israel to sin before God. Under his government, which pursued the policy of his predecessors regarding the support of the calf-worship, Israel's apostasy from the true God became greater and more confirmed than in the time of his father Jehu. God became angry at the increasing apostasy of King Jehoahaz and people of Israel, and allowed Syria to dominate over them. Under the domination of Syria, Israel was oppressed. It is at that time that Jehoahaz sincerely prayed to God for the first time in seventeen years, and God listened to his prayers and delivered Israel from the Syrian oppression.
God always listens to any person who prays sincerely for mercy after removing the iniquity from the heart. "If I regard iniquity in my heart, the Lord will not hear. But certainly God has heard me; He has attended to the voice of my prayer." (Psalms 66:18-19). Further down in 2 Kings chapter 13 we get another insight that God was gracious to Israel because of His ancient covenant with the patriarchs: "But the Lord was gracious to them, had compassion on them, and regarded them, because of His covenant with Abraham, Isaac, and Jacob, and would not yet destroy them or cast them from His presence." (2 Kings 13:23)
We see many examples in the Bible about God listening to sincere prayers even from very wicked people like Ahab (1 Kings 21:27-29) and the people of Nineveh during the time of Jonah the prophet (Jonah 3:5-10).
God is now looking across the earth to find those whose hearts are totally committed to Him. As it is written “The eyes of the Lord move to and fro throughout the whole earth that He may strongly support those whose heart is completely His.” (2 Chronicles 16:9, NASB).
When we approach the throne of God, let us sincerely seek Him in prayer. God will surely reward us for our sincerity. “It is impossible to please God without faith. Anyone who wants to come to Him must believe that God exists, and that He rewards those who sincerely seek Him.” (Hebrews 11:6, NLT)