Guarding secrets ensures self-control
Nahj al-Balāgha|Volume 1|Book 3|Chapter 162
١٦٢. وَقَالَ (عليه السلام): مَنْ كَتَمَ سِرَّهُ كَانَتِ الْخِيرَةُ بِيَدِهِ.
162. Amīr al-mu’minīn, peace be upon him, said: He who guards his secrets retains control in his own hands.