Isma`il, the eldest son of Imam Sadiq (as), had some money in his possession. When he learned that a person from the tribe of Quraish who was living in Madinah, was about to set out for Yemen, he decided to hand him some money so that he could purchase for him some merchandise for trade.
When Isma`il consulted his father, Imam Sadiq (as) about the issue, the Imam (as) inquired: “Does the man consume intoxicants?”
“People say so, but how do we know they speak the truth?” replied Isma`il.
The Imam (as) advised him, “It is not in your interest to give him the money.”
But Isma`il still gave his money to the person, who proceeded on his trip and in the course of it, embezzled the funds.
During the season of Hajj, both Imam Sadiq (as) and Isma`il went on pilgrimage. Isma`il was in the process of performing the Tawaf of the Ka’bah when the Imam (as) noticed that he was continually beseeching Allah to redeem his losses.
Manoeuvring himself through the crowd, the Imam (as) reached his son and placing his hand upon his shoulder, squeezed it lightly and said: “My Son! Do not seek anything from Allah needlessly, for you have no right upon Him. You should not have trusted the person in the first place. It is not upon others to rectify one’s own wrongdoing.”
“The people used to say that he consumed intoxicants but I had not seen him consume it!” said Isma`il.
The Imam (as) advised him further: “Consider the talks of the believers to be correct and do not trust a drunkard; be wary of giving money to those who are foolish and weak of understanding just as has been stated in the Qur’an). Who could be more foolish than a drunkard? Suggestions and intermediation of a drunkard in issues related to marriage should not be accepted nor should one place trust in his possession for he is bound to misappropriate it. A person who relies on a drunkard has no right whatsoever upon Allah that he may seek from Him compensation for damages suffered by him.”
Ba Mardum In Guneh Barkhord Konim, Page 35 , Biharul Anwar, Volume 4, Page 267
This clearly shows that Imam did not have the knowledge of unseen, or else he would he told his son that so and so will happen, instead of saying that “consider the talks of the believers to be correct”