حَدَّثَنَا مُحَمَّدُ بْنُ بَشَّارٍ، حَدَّثَنَا مَعْدِيُّ بْنُ سُلَيْمَانَ، أَنْبَأَنَا ابْنُ عَجْلاَنَ، عَنْ أَبِيهِ، عَنْ أَبِي هُرَيْرَةَ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ ‏"‏ مَنْ قَتَلَ مُعَاهِدًا لَهُ ذِمَّةُ اللَّهِ وَذِمَّةُ رَسُولِهِ لَمْ يَرَحْ رَائِحَةَ الْجَنَّةِ وَإِنَّ رِيحَهَا لَيُوجَدُ مِنْ مَسِيرَةِ سَبْعِينَ عَامًا ‏"‏ ‏.‏

It was narrated from Abu Hurairah that the Prophet (PBUH) said: “Whoever kills a Mu'ahid who has the protection of Allah and the protection of his Messenger, will not smell the fragrance of Paradise, even though its fragrance may be detected from a distance of Seventy years.” Translation Not Available

Book Ref: Sunan Ibn Majah Book 21 Hadith 2687
Web Ref:  Sunan Ibn Majah Vol 3 Book 21 Hadith 2687