It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him), mentioning his Lord, the Mighty and Majestic, said: "When My servant remembers Me in solitude, I remember him in solitude; and when he remembers Me in a gathering, I remember him in a gathering better than the gathering in which he remembered Me."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 12431