وَإِن نَّكَثُوا أَيْمَانَهُم مِّن بَعْدِ عَهْدِهِمْ… (And if they break their oaths): It means that, if they did not fulfill the terms of the covenant.

(…وَطَعَنُوا فِي دِينِكُمْ…) (defame your religion): And if they speak evil of your Faith; indeed, this is what the Jews and the Quraysh did. They broke every covenant or contract, and they spoke badly about Muslims. They broke all the promises and covenants with the Messenger of Allah (saws). Hence, the command for fighting was given:

…فَقَاتِلُوا أَئِمَّةَ الْكُفْرِ…(then, fight the leaders of disbelief): Leaders of disbelief are the war criminals. They are the main figures who incited the fighting against the Muslims, such as Abu Jahl, Al-Walid, Umayyah ibn Khalaf, and others. When the Prophet (saws) went out to Badr with a small group of believers to reclaim their wealth, they did not intend to fight. Abu Sufyan managed to flee with the caravan but, the polytheists in Mecca insisted on sending an aggressive army led by Abu Jahl Amr ibn Hisham, and Al-Walid ibn Al-Mughirah. They were the leaders of disbelief and misguidance, and they were the war criminals who tortured Suhaib and Bilal and harmed the Prophet, (saws). Thus, the permission to fight against them was granted.

(…إِنَّهُمْ لَا أَيْمَانَ لَهُمْ لَعَلَّهُمْ يَنتَهُونَ) (for indeed, there are no oaths [sacred] to them; [fight them that] they might cease): They have no commitment to treaty or covenant and they do not fulfill these agreements. A question may arise: Allah (swt) knows that they are committing breaches of trust, then why did He command His Messenger (saws) to sign agreements with them, such as the Treaty of Hudaybiyyah, and to sign agreements with the Jews in Al-Madinah? The answer is that Allah is legislating, while humans live in a world of causes. It is true that one should rely on the One Who grants the causes and effects, but in the world of causes, Allah wants Muslims to sign agreements, covenants, cooperate, and spread goodness and peace. The knowledge of Allah is all-encompassing, while we are commanded to seek and take all the necessary means. For indeed, Allah knows what they conceal.