neglected the execution of justice upon their implacable enemies, when
It was an ingenuous acknowledgment of an emperor, who, when one had committed murder, and he was importuned to spare his life, and he did it; suddenly after the same person committed wilful murder again; then there was complaint made to the emperor that he had committed murder twice,— No, saith the emperor, he is guilty of the former only; I am guilty of the latter.
Right Honourable, guilty persons that be by you sinfully acquitted, their sin God will charge upon your account. And therefore as you would not have the guilt of other men's sins upon you, hold on in the way of well-doing: let justice and judgment run down as mighty streams.
4. Fourthly, Right Honourable, consider this, those persons that have neglected the execution of justice upon their implacable enemies, when God has given them into their hands, those God hath left to perish basely and miserably. See it in Ahab, 1 Kings 21 compared with 22:23–37. God gives Benhadad into Ahab's hand, in ver. 40, 41, 'Because thou hast let a man go that I had appointed to destruction'—which was not signified to him by any extraordinary revelation, but by that ordinary dispensation, —'Therefore,' saith God, 'thy life shall go for his:' 22:31, 'Fight neither against small nor great, but against the king of Israel.' In which fight he lost his life at that time, and so perished miserably.
So concerning Saul in 1 Sam. 15:19, compared with the last of [first] Samuel 31:3, 4. Saul, he spares Agag, and he would shift off the command of the Lord; but for that God shifted him out of his kingdom. When he neglected to do justice upon an implacable enemy, when God had given him into his hands, God left him to perish and fall basely: ver. 26, 'Because thou hast rejected the word of the Lord, the Lord hath rejected thee from being king.' The Hebrew word, מאס מאסת, signifies to reject, to disdain, to cast off. The Lord rejected Saul, and he rejected the Lord; Saul disdained the Lord, and the Lord disdained Saul; he cast off the Lord, and the Lord cast off him.