The Prophet (ﷺ) gave him a dinar to buy a sacrificial animal or a sheep. He bought two sheep, sold one of them for a dinar, and brought him a sheep and dinar. So he invoked a blessing on him in his business dealing, and he was such that if had he bought dust he would have made a profit from it.
That there was a man who was not very sensible and he would make purchases. So his family came to the Prophet (ﷺ) and said: “O Messenger of Allah! Stop him (from making purchases).” So Allah’s Prophet (ﷺ) called him to prohibit him, and he said: “O Messenger of Allah! I have no patience for business.” So he said: “When you are buying, say: ‘Hand to hand, and no cheating.'” There is a narration on this topic from Ibn ‘Umar. The Hadith of Anas is a Hasan Sahih Gharib Hadith. This is acted upon according to the people of knowledge. They say that the free man can be prevented from selling and buying when his intellect is weak. This is the view of Ahmad and Ishaq. Some of the scholars did not think that the free person who had attained the age of responsibility could be prevented from that.
“I heard the Messenger of Allah (ﷺ) say: ‘Whoever equips a warrior in the cause of Allah until he is fully equipped, he will have a reward like his, until he dies or returns.”