A man came to visit Salman, and Salman had whatever food he had brought out for him, saying, "If the Messenger of Allah ﷺ had not forbidden us, or rather, if we had not been forbidden, to go to extra trouble for one another, I would have gone to trouble for you."
حدثنا عفان حدثنا قيس بن الربيع حدثنا عثمان بن شابور رجل من بني أسد
أن سلمان دخل عليه رجل فدعا له بما كان عنده وقال لولا أن رسول الله ﷺ نهانا أو لولا أنا نهينا أن يتكلف أحدنا لصاحبه لتكلفنا لك
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Its isnad is daif due to the obscurity of Uthman bin Sabur, but Hakim graded it sahih in 4/123, and Dhahabi agreed with him, via the route of Amash from Shaqiq. It is also found in Bayhaqi's Shuab 7/94, number 9598.