Hadith 40, 40 Hadith Qudsi
On the authority of Abu Sa'id al-Khudri (may Allah be pleased with him), who said that the Messenger of Allah (ﷺ) said:
Allah will say to the inhabitants of Paradise: O inhabitants of Paradise! They will say: O our Lord, we present ourselves and are at Your pleasure, and goodness rests in Your hands. Then He will say: Are you contented? And they will say: And how should we not be contented, O Lord, when You have given to us that which You have given to no one else of Your creation? Then He will say: Would you not like Me to give you something better than that? And they will say: O Lord and what thing is better than that? And He will say: I shall cause My favour to descend upon you and thereafter shall never be displeased with you.

It was related by al-Bukhari (also by Muslim and at-Tirmidhi).
عَنْ أبي سَعِيدٍ الخُدّريّ رَضِيَ اللهُ عَنْهُ قَالَ: قَالَ النَّبِىُّ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ
 إنَّ اللهَ يَقُولُ لأَهْلِ الجَنَّةِ : يَا أهْلَ الجَنَّةِ . فَيَقُولُون : لَبَّيْكَ رَبَّنا وسَعْدَيْكَ ، والخَيْرُ في يَدَيْكَ. فَيَقُولُ : هَلْ رَضِيتُم ؟  فَيَقُولُونَ : وَما لَنا لَا نَرْضَىى يَا رَبّ ،  وَقَدْ أَعْطَيْتَنا مَا لمْ تُعْطِ أَحَداً مِنْ خَلْقِكَ .  فَيَقُولُ : أَلا أُعْطِيكُمْ أَفْضَلَ مِنْ ذَلِك ؟  فَيَقُولُونَ :  يَا رَبّ وأيُّ شيءٍ أَفْضَلُ مِنْ ذَلِك ؟ فَيَقُولُ : أٌحِلُّ عَلَيْكُمْ رِضْواني ، فَلا أَسْخَطُ عَلَيْكُمْ بَعْدَهُ أَبداً 
رواه البخاري (وكذلك مسلم والترمذي)