Sahih Bukhari Volume 6, Book 65, Hadith 4733

حَدَّثَنَا أَبُو نُعَيْمٍ، حَدَّثَنَا عُمَرُ بْنُ ذَرٍّ، قَالَ سَمِعْتُ أَبِي، عَنْ سَعِيدِ بْنِ جُبَيْرٍ، عَنِ ابْنِ عَبَّاسٍ ـ رضى الله عنه ـ قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم لِجِبْرِيلَ ‏"‏ مَا يَمْنَعُكَ أَنْ تَزُورَنَا أَكْثَرَ مِمَّا تَزُورُنَا فَنَزَلَتْ ‏{‏وَمَا نَتَنَزَّلُ إِلاَّ بِأَمْرِ رَبِّكَ لَهُ مَا بَيْنَ أَيْدِينَا وَمَا خَلْفَنَا‏}‏‏"‏

Narrated By Ibn Abbas : The Prophet said to Gabriel, "What prevents you from visiting us more often than you visit us now?" So there was revealed: 'And we (angels) descend not but by the command of your Lord. To Him belongs what is before us and what is behind us...' (19.64)