The Prophet of Allah sal Allahu alayhi wa sallam narrated, "When those deserving of Paradise would enter Paradise, the Blessed and the Exalted would ask: Do you wish Me to give you anything more? They would say: Have You not brightened our faces? Have You not entered us into Paradise and saved us from Fire? He (the narrator) said: He (Allah) would lift the veil, and of things given to them nothing would be dearer to them than the sight of their Lord, the Mighty and the Glorious." [Saheeh Muslim]

The Prophet sal Allahu alayhi wa sallam narrated this duaa in a hadeeth in Sunan an-Nisaa'i (authenticated by Shaykh Albaani):

اللَّهُمَّ إِنِّي أَسْأَلُكَ لَذَّةَ النَّظَرِ إِلَى وَجْهِكَ وَالشَّوْقَ إِلَى لِقَائِكَ

Allahumma Innī As’aluka Ladhdhata an-Naẓari ilā Wajhika wash Shawqa ilā Liqā’ik

O Allah, I ask You for the delight of gazing at Your Countenance and the eagerness of meeting You