I was present with Safwan, Jundab, and his companions when he was giving them his final counsel.They asked, "Did you hear anything from the Messenger of Allah ﷺ?"He replied, "I heard him say, 'Whoever lets his deeds be heard of, Allah will expose him on the Day of Resurrection, and whoever causes division, Allah will divide against him on the Day of Resurrection.'"They said, "Give us your counsel."He said, "The first part of a person to rot is his belly, so whoever is able to eat nothing but what is wholesome, let him do so. And whoever is able to keep nothing between himself and Paradise, not even a handful of blood he has shed, let him do so."
شهدت صفوان وجندبا وأصحابه وهو يوصيهم فقالوا: هل سمعت من رسول الله ﷺ شيئا؟ قال: سمعته يقول: من سمع سمع الله به يوم القيامة قال: ومن يشاقق يشقق الله عليه يوم القيامة فقالوا: أوصنا. فقال: إن أول ما ينتن من الإنسان بطنه فمن استطاع أن لا يأكل إلا طيبا فليفعل، ومن استطاع أن لا يحال بينه وبين الجنة بملء كفه من دم أهراقه فليفعل.
Bukhari narrated it in "The Rulings" (7152) from Ishaq Wasiti, "Khalid narrated to us, from Jareeri, from Tarif Abu Tamima," who said, then he mentioned it.At the end there appears Firabri's statement to Bukhari, "Who says, 'I heard the Messenger of Allah,' ﷺ Jundab?" He said, "Yes, Jundab."His saying, "Whoever causes hardship, Allah will make things hard for him," could be understood as relating to hardship and harm, by burdening people with what is difficult for them at the hands of their rulers.It could also be understood as relating to shiqaq, which is disagreement and separation from the community, as in the verse, "and whoever opposes the Messenger after guidance has become clear to him" [Nisa 4:115]. Fath al-Bari (130/13).