Do not covet/desire anything belonging to one’s fellow man. (10th of the 10 Commandments)
“Do not covet.” Shmos 20:14
Coveting is where a person makes an effort to put his thoughts into action.
He sends many friends to his fellow to negotiate until he takes it from him.
Even if he pays a great price for it he violates this prohibition.
This occurs when a son- in- law pressures his father-in-law before the wedding that he should give him a certain item that was not stipulated in the marriage agreement.
Even if the father-in-law agrees the son-in- law violates this prohibition not to covet.