﴿ وَٱتَّبِعُوٓا۟ أَحْسَنَ مَآ أُنزِلَ إِلَيْكُم مِّن رَّبِّكُم مِّن قَبْلِ أَن يَأْتِيَكُمُ ٱلْعَذَابُ بَغْتَةًۭ وَأَنتُمْ لَا تَشْعُرُونَ ﴾

“And ere that suffering comes upon you of a sudden, without your being aware [of its approach], follow the most goodly [teaching] that has been revealed unto you by your Sustainer,”

In verse 55, it was said: وَاتَّبِعُوا أَحْسَنَ مَا أُنزِلَ إِلَيْكُم (and follow the best of what has been sent down to you). The second phrase أَحْسَنَ مَا أُنزِلَ (the best of what has been sent down) means the Qur'an, and the whole Qur'an is but ahsan, the best - and the Qur'an can be called: اَحسَںَ و اکمل (best) also in the sense that out of all scriptures - Torah, Injil, Zabur - revealed from Allah Ta’ ala, the Qur'an is the best and the most perfect. (Qurtubi)