3. Muhammad ibn Yahya has narrated from ‘Abd Allah ibn Muhammad from Ali ibn al-Hakam from Aban ibn ‘Abd al-Rahman ibn abu ‘Abd Allah who has said the following: “This is concerning my question before abu ‘Abd Allah , about exchanging one slave for two slaves and a slave for a slave and some dirhams. He (the Imam) said,

‘It is not harmful in the case of all animals if it (the deal) is simultaneous.’”