Shaikh Sadi was a scholar of Islam. He was a teacher and author of two famous books, Bostan and Gulistan. His contemporaries were Ibn Arabi (1165-1240), jalal uddin Rumi (1207-1273), Farid uddin Attar 1150-1222) and many others.
Here is a quote of Shaikh Sadi.
Wash thy hands, o wise one, from a friend,
who is sitting together, with thy foe