Mishkat al-Masabih 4 Prayer كتاب الصلاة 774

وَعَنْ أَنَسٍ قَالَ: كَانَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ إِذَا دَخَلَ رَجَبٌ قَالَ: «اللَّهُمَّ بَارِكْ لَنَا فِي رَجَبٍ وَشَعْبَانَ وَبَلِّغْنَا رَمَضَانَ» قَالَ: وَكَانَ يَقُولُ: «لَيْلَةُ الْجُمُعَةِ لَيْلَةٌ أَغَرُّ وَيَوْمُ الْجُمُعَةِ يَوْمٌ أَزْهَرُ» . رَوَاهُ الْبَيْهَقِيُّ فِي الدَّعَوَاتِ الْكَبِيرِ

Anas said that when Rajab came God’s Messenger said, “O God, bless us in Rajab and Sha’ban and bring us to Ramadan.” He also quoted him as saying, “Thursday night is a very bright night and Friday is a shining day.” Baihaqi transmitted it in [Kitab] ad-Da’awat al-kabir .