The peril of abandoning "I do not know"
Nahj al-Balāgha|Volume 1|Book 3|Chapter 85
٨٥. وَقَالَ (عليه السلام): مَنْ تَرَكَ قَوْلَ لَا أَدْرِي أُصِيبَتْ مَقَاتِلُهُ.
85. Amīr al-mu’minīn, peace be upon him, said: Whoever abandons saying, “I do not know” meets his destruction.