When you observe prayer after (the two obligatory rak'ahs) of Jumu'ah, you should observe four rak'ahs (and 'Amr in his narration has made this addition that Ibn Idris said this on the authority of Suhail): And if you are in a hurry on account of something, you should observe two rak'ahs in the mosque and two when you return (to your house).
قَالَ رَسُولُ اللَّهِ ﷺ إِذَا صَلَّيْتُمْ بَعْدَ الْجُمُعَةِ فَصَلُّوا أَرْبَعًا زَادَ عَمْرٌو فِي رِوَايَتِهِ قَالَ ابْنُ إِدْرِيسَ قَالَ سُهَيْلٌ فَإِنْ عَجِلَ بِكَ شَىْءٌ فَصَلِّ رَكْعَتَيْنِ فِي الْمَسْجِدِ وَرَكْعَتَيْنِ إِذَا رَجَعْتَ