2. Surah Al-Nasr In the name of Allah, the Beneficent, the Merciful
When the victory of Allah has come and the conquest
And you see the people entering into the religion of Allah in multitudes,
Then exalt [Him] with praise of your Lord and ask forgiveness of Him. Indeed, He is ever Accepting of repentance. 

3. Lessons from Surah Al-Nasr
Allah s.w.t. helped Rasulullah s.a.w. during the opening of Mekkah
More people started to revert to Muslims after the opening of Mekkah
Allah s.w.t. asked Man to put always remember Him by glorifying Him
To seek forgiveness and repent to Allah as he is the Most Forgiving and accepts repentance

4. Reason Behind the Revelation
Narrated from ‘Abdurrozzaq in the book of al-Mushannaf, from Ma’mar sourced from az-Zuhri, when Rasulullah s.a.w. entered Mekkah, Khalid Bin Walid was instructed to enter Mekkah from the lowlands to attack the Quraisy (those who initiate the fight) and took away their weapons after attaining victory over them. Hence many of the Quraisy entered Islam. This Surah is revealed in relation to above event, as a command to praise and glorify Allah s.w.t. for the victory and seek forgiveness for all the sins that have been committed.