عَنْ جَابِرٍ قَالَ: إِنَّ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ نَهَى عَنِ الثُّنْيَا إِلَّا أنْ يُعلمَ. رَوَاهُ التِّرْمِذِيّ

Abu Huraira said God’s Messenger forbade two transactions combined in one (Making part-payment with the promise of the remainder later

or selling an article for a stated price on condition that the buyer sells article for a stated price. Malik, Tirmidhi, Abu Dawud and Nasa‘i transmitted it.