The Prophet, sallallaahu alayhi wa sallam, told Abu Thar, may Allaah be pleased with him: "O Abu Tharr! You are a weak person, and it is a trust, and on the Day of Judgment it will be sorrow and regret, except for the one who really fulfils its rights and obligations.” What is the meaning of the expression: “You are a weak person”?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.

The narration on which you asked the meaning of some of its wording is reported by Imaam Muslim and Ahmad . Abu Tharr asked: "O Prophet of Allaah, why don’t you use me (in running the affairs of Muslims and leading the people)?” He said: “The Prophet put his hand on my shoulder then said: "O Abu Tharr! You are a weak person, and it is a trust, and on the Day of Judgment it will be sorrow and regret except for the one who really fulfils its rights and obligations.” The weakness that is mentioned in the narration is the inability of fulfilling the tasks of ruling and leading people. An-Nawawi said: 'This narration is a great principle in avoiding being appointed as a ruler or governor, especially for he who is not able to fulfil its tasks.'

Allaah Knows best.