Quraish press Abu Talib to stop his nephew. When his uncle asks him to spare them both, the Prophet ﷺ says he would not give up his mission even if they put the sun in his right hand and the moon in his left. Abu Talib replies: go and preach what you please, I will never forsake you.
As the book dates it: probably the 6th year of Prophethood (the book says the date is not recorded)
O my uncle! by Allah if they put the sun in my right hand and the moon in my left on condition that I abandon this course … I would not abandon it.