Musannaf Ibn Abi Shayba 33:1247

Muhammad ibn Bishr narrated to us, he said: Mis'ar narrated to us, from Abu 'Awn, who said: The people of goodness, when they met, would advise one another with three things, and when they were absent, they would write to one another with three things: Whoever works for his Hereafter, Allah will suffice him in his worldly life. Whoever rectifies what is between him and Allah, Allah will suffice him against the people. And whoever rectifies his inner self, Allah will rectify his outer self.