Is it true that Abu Mihjan (may Allah be pleased with him) drank alcohol, and that Sa'd ibn Abi Waqqas (may Allah be pleased with him) said: "I will not flog you for alcohol after today," and why did Sa'd not carry out the حد (hadd) punishment on him?

The Companion Abu Mihjan al-Thaqafi was afflicted with drinking intoxicants. Authentic narrations have been reported about his story of going out to fight in the Battle of al-Qadisiyyah after he had been restrained by the order of Sa'd ibn Abi Waqqas due to his drinking of wine. Abu Mihjan fought valiantly in the battle. When he returned and placed his foot back in the shackles, Sa'd's wife informed Sa'd of what had happened. Sa'd then said: "No, by Allah, from today onwards I will not strike a man through whom Allah has granted the Muslims such a victory," and he released him. Then Abu Mihjan said: "I used to drink it when the prescribed punishment was inflicted upon me, and I would be purified by it. But if it disgraced me, then no, by Allah, I will never drink it again."

What Sa'd did is not considered a suspension of Allah's prescribed punishments (Hudud), but rather it falls under the category of expiating a bad deed with a wiping good deed. Abu Mihjan's sacrificing himself in the way of Allah and his jihad overshadowed his bad deed, and signs of sincere repentance appeared from him. Moreover, his surrendering himself and voluntarily placing his foot in the shackles made him deserving of having his punishment waived. Some scholars have even stated that the delay of the punishment was because prescribed punishments are not carried out in a land of war. Delaying a punishment due to a valid impediment is something that the Sharia permits, just as it is delayed for a pregnant woman or a sick person.