Nahj al-Balāgha
Hadith 2210٣٦٤. وَقَالَ (عليه السلام): لَا تَسْأَلْ عَمَّا لَا يَكُونُ، فَفِي الَّذِي قَدْ كَانَ لَكَ شُغُلٌ.
364. Amīr al-mu’minīn, peace be upon him, said: Do not ask about things which may not happen because you have enough to worry about with what happens.