Musannaf Ibn Abi Shaybah

Ismail narrates that it is reported from Hazrat Sha’bi regarding four men who testified against a man for committing adultery, and one of the witnesses was not just. He said: The punishment (hadd) will be dropped from that person because the witnesses must be four.

Hazrat Ash'ath narrates that Hazrat Sha'bi said: When four witnesses testify to adultery and all of them are not just, then they will not be flogged.

Hazrat Ash'ath narrates that Hasan Basri said: When four men testify against a person for adultery and these four are not declared just (‘adil), then the punishment (hadd) will be dropped from that person and none of these four will be flogged.