Selections from The Sayings and Preaching of Amir al-Muminin Ali ibn Abi Talib (Peace Be Upon Him) Including His Replies to Questions and Maxims Expressed for Various Purposes.Translated by Sayyid Ali Reza
وَقَالَ (عليه السلام):
Amir al-mu'minin, peace be upon him, said:
لاَتَسْأَلْ عَمَّا لاَ يَكُونُ،
Do not ask about things which may not happen
فَفِي الَّذِي قَدْ كَانَ لَكَ شُغُلٌ.
because you have enough to worry about with what happens.