I need to reiterate this: God is merciful and patient, but that does not mean that he does not care and he will not proclaim justice. Ahab was a bloody tyrant. He was doomed to death. Such is the fate of all tyrants: and he went to his death warned by a prophet.
12 Then the messenger who went to summon Micaiah spoke to him saying, “Behold, the words of the prophets are uniformly favorable to the king. So please let your word be like one of them and speak favorably.” 13 But Micaiah said, “As the Lord lives, what my God says, that I will speak.”
14 When he came to the king, the king said to him, “Micaiah, shall we go to Ramoth-gilead to battle, or shall I refrain?” He said, “Go up and succeed, for they will be given into your hand.” 15 Then the king said to him, “How many times must I adjure you to speak to me nothing but the truth in the name of the Lord?” 16 So he said,
“I saw all Israel
Scattered on the mountains,
Like sheep which have no shepherd;
And the Lord said,
‘These have no master.
Let each of them return to his house in peace.’”
17 Then the king of Israel said to Jehoshaphat, “Did I not tell you that he would not prophesy good concerning me, but evil?”
18 Micaiah said, “Therefore, hear the word of the Lord. I saw the Lord sitting on His throne, and all the host of heaven standing on His right and on His left. 19 The Lord said, ‘Who will entice Ahab king of Israel to go up and fall at Ramoth-gilead?’ And one said this while another said that. 20 Then a spirit came forward and stood before the Lord and said, ‘I will entice him.’ And the Lord said to him, ‘How?’ 21 He said, ‘I will go and be a deceiving spirit in the mouth of all his prophets.’ Then He said, ‘You are to entice him and prevail also. Go and do so.’ 22 Now therefore, behold, the Lord has put a deceiving spirit in the mouth of these your prophets, for the Lord has proclaimed disaster against you.”