'And if they turn away' means: from responding to the good news of their defeat and their lack of steadfastness due to what He cast into their hearts of terror. This is supported by His saying: 'Know that Allah' means: He who has complete knowledge of everything, 'is your protector' means: He is in charge of your affairs. He works with you as one who takes care of the affairs of one he loves, striving to obtain what benefits him and to repel what harms him. So, He will certainly support you. Then He resumed praising Him with what He is worthy of, introducing His greatness and encouraging reliance upon Him, saying: 'Excellent is the protector.' He did not include the conjunction here because the command is to know, and believing in Him being a protector is obligatory in itself, not for any other reason. This is unlike what is mentioned at the end of Al-Hajj, where the command there is to hold fast. 'And excellent is the helper' means: So do not fear them at all, even if their numbers increase and their power grows strong. Do not leave them until there is nothing but the word of Allah.