{ Truly the worst of animals in the sight of Allah are those who have disbelieved, for they have not believed. Those of them with whom you have made a pledge but then they broke their pledge every time, not being devout. If indeed you get to them in warfare, use them to drive away those who come after them, that perchance they might be reminded } Al-anfal 55-57

{ Truly the worst of animals in the sight of Allah } : that is, in His judgment and awareness concerning those befallen with two attributes: the first attribute is that a Disbeliever [Kafir], someone who persists in his disbelief and is fixed on it, can not change from it whatsoever; the second is that he perpetually breaks covenants. … Know that the Most High at times guides His Messenger to gentleness and kindness in numerous verses, including: { We have only sent you as a mercy to the worlds } [Al-anbiyaa 107], and: { So pardon them, and seek forgiveness for them, and consult with them regarding the issue } [Al ‘Imran 159]. But sometimes His guidance is to exert harshness and severity, as in this verse; this is because the Most High, when He mentions those who break their covenant every time, makes it clear how they must be treated.