Is it permissible to take the amount exceeding the farm's price set by the seller as a commission, in addition to the brokerage commission, without the knowledge of the seller or the first buyer? And is the person who directed me to the broker entitled to a commission?

It is permissible for brokers to take an additional amount over the original price of the land, whether they add another commission or not, provided they do not lie to the buyer. If there is a partnership between the brokers, the partner must be given his share of the commission. However, if the buyer has asked you to purchase on his behalf as an agent, you are not permitted to take an additional amount except with his consent, and the seller's knowledge is not a condition in any of the foregoing.