Prophets must be blameless
We said that the purpose of the coming of the prophets was to guide and instruct people on the true path, and naturally, if the leader and leader himself is vicious and does unworthy deeds, he will not be able to orient people to purity and righteousness.Therefore, it is very necessary that the divine prophets be protected from all kinds of sins and vices, so that people go with them along the path to happiness.
In other words, if someone calls people to truthfulness and conscientiousness, and he himself is a liar, or sometimes he will lie or commit treason, then his words will never have the proper impact on people. Also, if the prophets of the Lord are not protected from mistakes and transgressions and people think that by their statements (expressing divine decrees) they will doom themselves to mistakes, then they will not perceive their statements with confidence and as a result, following their path cannot be perceived. Right and the realization of their goal cannot be realized. Yes, the Almighty Lord does not elect for prophecy and prophetic mission those who are not protected from unbelief in God and sins, he elects for this great work those who are cleansed of all vices and in the future will be fully protected from all mistakes and errors.
Prophets must perform a miracle
One who has a pure soul will not accept any statements without reason, and if someone accepts any statements without reason, that is, without proper arguments, this means that he asserts his mental defect. Therefore, it is necessary that all divine prophets have strong arguments and evidence to confirm their prophecy in order to prove to people their prophetic mission and that they are directed by the Lord Almighty.
One of the arguments proving the connection of the prophets with the divine world is the performance of a miracle on their part. A miracle means a work that others are not able to do during the period of the prophets, like the resurrection of the dead, the cure of incurable diseases.
Imam Sadiq said on this occasion: - Each prophet must have a testimony that will confirm the correctness of his statements so that people believe in him.