Musnad Ahmad 31:834

Ali ibn Ishaq narrated to us, Abdullah informed us, Malik ibn Anas informed us, from Zayd ibn Aslam, from Ata ibn Yasar, from Abu Sa’id al-Khudri, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Indeed, Allah will say to the people of Paradise: 'O people of Paradise.' They will say: 'At Your service, our Lord, and at Your command.' He will say: 'Are you satisfied?' They will say: 'And why should we not be satisfied, when You have given us what You have not given to anyone among Your creation?' He will say: 'I shall give you something better than that.' They will say: 'O our Lord, and what thing is better than that?' He will say: 'I shall bestow My pleasure upon you, so I shall never be angry with you after it, ever.'"