4. Muhammad ibn Yahya has narrated from Ahmad ibn Muhammad from Ali al-Nu’man from ibn Muskan from Sulayman ibn Khalid who has said the following: “This is concerning my question before abu ‘Abd Allah , about the case of a man who makes advance payment for farms and takes a certain amount of his foodstuff and a certain amount remains. The other party offers him the remaining of his capital. He (the Imam) said, ‘He must accept it; it is lawful.’ I then said, ‘He sells his foodstuff that he has received and it doubles.’ He (the Imam) said, ‘If he does, it is lawful.’ I then asked him (the Imam) about a man who makes advance payment for what is not a farm or palm trees. He (the Imam) said, ‘He must name something for an appointed time.’”