Mishkat al-Masabih 3832
Abu Huraira reported God’s Messenger as saying, “I was shown the first three to enter paradise:
a martyr, a continent man who refrains from what is unlawful, and a slave who worships God well and serves his patrons sincerely." 

Tirmidhi transmitted it.
وَعَنْ أَبِي هُرَيْرَةَ أَنَّ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ قَالَ: 
" عَرَضَ عَلَيَّ أَوَّلُ ثَلَاثَةٍ يَدْخُلُونَ الْجَنَّةَ: شَهِيدٌ وَعَفِيفٌ مُتَعَفِّفٌ وَعَبَدٌ أَحْسَنَ عبادةَ اللَّهِ ونصح لمواليه ". رَوَاهُ التِّرْمِذِيّ