(They) remain in them timelessly, for ever. Allah's promise is true. He is the Almighty, the All-Wise. (Qur'an, 31:9)
Allah has bought from the believers their selves and their wealth in return for the Garden. They fight in the Way of Allah and they kill and are killed. It is a promise binding on Him in the Torah, the Gospel and the Qur'an and who is truer to his contract than Allah? Rejoice then in the bargain you have made. That is the great victory. (Qur'an, 9:111)
Even if there was a Qur'an which moved mountains, or split the earth open or spoke to the dead..! On the contrary! The affair is Allah's altogether. Do those who believe not know that if Allah had wanted to He could have guided all mankind? Those who do not believe will not cease to be struck by disaster for what they have done -or a disaster will happen close to their homes- until Allah's promise is fulfilled. Allah will not fail to keep His promise. (Qur'an, 13:31)
Gardens of Eden which the All-Merciful has promised to His servants in the Unseen. His promise is always kept. (Qur'an, 19:61)
They ask you to hasten the punishment. Allah will not break His promise. A day with your Lord is equivalent to a thousand years in the way you count. (Qur'an, 22:47)