In discussion, a Muslim brother conceded that, even though he accepted prophets
were free of sin, he could not agree that they were incapable of making mistakes/errors.
Is there any evidence in the Qur’an that prophets are totally and absolutely free of sin and unable to make mistakes? Also, is the condition of being free of sin and error applicable only to specific prophets? We know that Adam (A.S) was advised not to eat from the forbidden tree rather than being commanded not to eat from it. So, even though he did not disobey Allah and thus did not commit a sin, he erred in not accepting the Creator’s advice.

Allah Almighty names 18 prophets whom He tells us,
These are they whom Allah has guided; therefore, follow their guidance. Qur’an 6:84 – 89

If a prophet were to commit a sin or make a mistake it would not be safe to follow him.
Even if he made that mistake in private and not in public, he would lose credibility with himself.
It was Allah’s will that the Prophet Adam (A.S) ate from that particular tree because human beings have been deputised to be the vicegerents of Allah on earth. Had he not eaten from it he would never have descended from the heavens to this earth. Furthermore, as there was no sin before
he arrived here, the concept of the forbidden tree is not categorised under forbidden acts in Islamic Law.

Without the prophets being free of all types of error and mistake, people would not trust them and without trust, the whole concept of Prophethood could not exist.