They swore allegiance to you under the tree

I hope to get from you the interpretation of this verse: In The Name of Allah The Merciful The Most Merciful: “Allah was pleased with the believers when they swore allegiance to you under the tree, for He knew well what was in their hearts, and sent down tranquility on them, and rewarded them with an expeditious victory “ (The Holy Qur’an Surah Al-Fath: 18) and who are the believers this verse is mentioning?

Knowing Allah occurs by purifying the self

Verily, knowing Allah occurs by purifying the self, and the purification of the self is not accomplished except by applying the Jurisprudence and asceticism in the world, and spending in the path of Allah, and possessing the best of morals/manners, and loving for Allah and hating for Allah

I am giving them a solution, and if they are reasonable

Greetings to the beloved believers in all the cities of Iran.
Peace be upon the beloved ones in all cities of Iran who have been imprisoned for their ideology. May Allah help you tolerate the harm for the sake of Allah.