This composition is one of the many Prophet Muhammad's Salla Allahu Alaihi Wa Sallam sayings (PBUH) or what is called (Prophetic Sunna) and means:
The best of you (you mankind) is to learn the Holy Quran
and teach it.
For more explanation: There are many ways and preferences for the MAN to be the best and one of them
is what Prophet Sayyeduna Muhammad Salla Allahu Alaihi Wa Sallam just said in the above Hadeeth(Prophetic Sunna).
Furthermore, The meaning of getting learn Quran is not how to read but, also(and this is the reason and the purpose of learning) to learn the reason and the purpose behind every single word of the Holy Quran's words, then to do and act exactly as the Quran says.
This been written in Thuluth Script!