Cursing a Muslim and the sale of the 'arabun (earnest money)

Question:
And the desire of the Shaykh, by Allah, is that if a person curses another as a result of a mistake the other made, is one of them expelled from the mercy of Allah, or does he pray?

Answer:
It is not permissible to curse except one whom Allah has cursed or whom the Messenger (peace and blessings be upon him) has cursed. As for anyone else, even if he is a sinner and a transgressor, it is not permissible to curse him. So the Muslim keeps his tongue pure from cursing. This is a serious matter, because if a person utters a curse, he utters a serious word that goes to the one it was said about. If he is worthy of it, otherwise it returns to the one who said it. Yes. So he becomes the one cursed; the one who said it becomes the one cursed. So the matter is very serious. Yes. Yes. According to Imam Ahmad, if one buys or pays an 'arabun (earnest money) and then withdraws from the purchase or backs out, the seller has the right to take the 'arabun. This was the practice of 'Umar (may Allah be pleased with him), and Imam Ahmad adopted this practice. The sale of the 'arabun is permissible, and it is lawful for the seller if the buyer backs out of the purchase, because he has lost the customers, and it may have also tied up the goods. Yes. Rejection of what? No, if the rejection is from the seller, he has no right to the 'arabun. Yes.