A companion of Imam Ali Reza (a.s.) said:
“Allah never to show us the day (of your death) but if something happened, to whom will be Imamat belong?”
Imam (a.s.) pointed to Imam Taqi (a.s.) with his hand while he was standing in front of him.
The companion said: “May I be ransom, this is a child of three years old.”
“That does not harm him,” Imam (a.s.) replied. “Jesus (a.s.) gave evidence (of his mission) when he was less than three years old.”
π Kitab al-Irshad, Chapter of Imam Taqi (a.s.)