Sunan an-Nasa'i, Book 25, Hadith 100 (In-Book) ⓘ
It was narrated that Abu Hurairah said: "The Messenger of Allah said: 'Whoever spends on a pair (of things) in the cause of Allah, the gatekeepers of Paradise will call him from the gates of Paradise (saying): O So-and-so, come and enter!' Abu Bakr said: 'O Messenger of Allah, such a person will never perish or be miserable.' The Messenger of Allah said: 'I hope that you will be one of them.'"
أَخْبَرَنَا عَمْرُو بْنُ عُثْمَانَ، قَالَ حَدَّثَنَا بَقِيَّةُ، عَنِ الأَوْزَاعِيِّ، قَالَ حَدَّثَنِي يَحْيَى، عَنْ مُحَمَّدِ بْنِ إِبْرَاهِيمَ، قَالَ أَنْبَأَنَا أَبُو سَلَمَةَ، عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " مَنْ أَنْفَقَ زَوْجَيْنِ فِي سَبِيلِ اللَّهِ دَعَتْهُ خَزَنَةُ الْجَنَّةِ مِنْ أَبْوَابِ الْجَنَّةِ يَا فُلاَنُ هَلُمَّ فَادْخُلْ " . فَقَالَ أَبُو بَكْرٍ يَا رَسُولَ اللَّهِ ذَاكَ الَّذِي لاَ تَوَى عَلَيْهِ . فَقَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " إِنِّي لأَرْجُو أَنْ تَكُونَ مِنْهُمْ " .
also referenced under: Hadith 3184 (Reference) & Volume 4, Book 25, Hadith 3186 (DarusSalam)