The Prophet ﷺ said, "Whoever spends a pair of anything in the cause of Allah will be called by the keepers of Paradise, each keeper at his own gate, saying, 'Come this way!'"Abu Bakr said, "Messenger of Allah, that is the one who suffers no loss."The Prophet ﷺ replied, "I truly hope you will be among them."
عن النبي ﷺ قال: من أنفق زوجين في سبيل الله دعاه خزنة الجنة- كل خزنة باب- أي قل هلم، قال أبو بكر: يا رسول الله ذاك الذي لا توى عليه، فقال النبي ﷺ: إني لأرجو أن تكون منهم.
Bukhari narrated it in Jihad and Expeditions (2841), and Muslim in Zakat (1027:86), both through Shayban bin Abdul-Rahman, from Yahya bin Abu Kathir, from Abu Salama bin Abdul-Rahman, that he heard Abu Hurairah, and he mentioned it.His words, "a pair," mean two things of any kind that one spends. The word "zawj" can apply to a single item or to two, and what is meant here is a single item, as stated in Fath al-Bari (6/49).His words, "O so-and-so" are a truncated form of "fulan" (someone).His words, "that one suffers no towa," mean no loss and no waste. It comes from "tawa," meaning destruction, as stated by Ibn Athir.