Abdullah bin Samit reported,

He was with Abu Dharr when his stipend was paid out, and Abu Dharr had a slave girl with him who was attending to his needs. After she had finished, seven coins remained, and he instructed her to use them to buy fulus.I said to him, "Why not save it for some need that may befall you, or for a guest who may come to stay with you?"He replied, "My dear friend ﷺ entrusted me with this, that any gold or silver that is hoarded away will be burning coals upon its owner until he spends it in the path of Allah."

حدثنا عفان حدثنا همام حدثنا قتادة عن سعيد بن أبي الحسن

عن عبد الله بن الصامت

أنه كان مع أبي ذر فخرج عطاؤه ومعه جارية له فجعلت تقضي حوائجه قال ففضل معها سبع قال فأمرها أن تشتري به فلوسا قال قلت له لو ادخرته لحاجة تنوبك أو للضيف ينزل بك قال إن خليلي عهد إلي أن أيما ذهب أو فضة أوكي عليه فهو جمر على صاحبه حتى يفرغه في سبيل الله عز وجل