Translation:

26. While the Unbelievers got up in their hearts heat and cant--the heat and cant of Ignorance--Allah sent down His tranquillity to His Apostle and to the Believers and made them stick close to the command of self-restraint; and well were they entitled to it and worthy of it. And Allah has full knowledge of all things.

Notes (Tafseer)

4907. While the Unbelievers were blustering and excited, and meticulously objected to introductory words such as "In the name of Allah, Most Gracious, Most Merciful (they did not like the titles), the Prophet remained calm and collected, and got the substance of their demands embodied in the Treaty without worrying about words. Even though the terms of the Treaty appeared to the companions, at first, to be unfair to Muslims, they remained faithful to their Leader and showed trust in his better judgment, a trust that was vindicated by the events that followed.

4908. Cf. above xlviii. 18, and n. 4894.

4909. It=Tranquillity. Their calmness amid much provocation was a gift of Allah; they had earned a right to it by their obedience and discipline, and showed themselves well worthy of it.