مُسْنَدُ أَحْمَدَ
Musnad Ahmad 3653
Musnad of Abdullah bin Mas'ood
It was narrated that 'Abdullah bin Mas'ood (رضي الله عنه) said: The Messenger of Allah (ﷺ) said: “Do not buy fish in the water, for it is an ambiguous transaction."
Musnad Ahmad 3676Its isnad is da’eef]