It is narrated from Sayyiduna Mu'adh bin Anas al-Juhani (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "Allah Almighty says: Whenever My servant remembers Me within himself, I remember him in an assembly of My angels; and whenever he remembers Me in an assembly, I remember him in the Highest Companionship (al-Rafiq al-A'la, the loftiest station)."
Hadith Referenceالمعجم الكبير للطبراني / باب الميم / 17526