The Messenger of Allah ﷺ used to say: "Whoever prays four rak'ahs before Zuhr and four after, Allah, the Mighty and Sublime, will forbid him from the Fire." (Using translation from Nasāʾī 1814)
أَنَّهَا سَمِعَتْ رَسُولَ اللهِ ﷺ يَقُولُ مَنْ صَلَّى أَرْبَعًا قَبْلَ الظُّهْرِ وَأَرْبَعًا بَعْدَ الظُّهْرِ حَرَّمَهُ اللهُ عَلَى النَّارِ