Is it permissible to buy from a vegetable vendor who refuses to lower the price and swears he will not reduce it?

Swearing in sales is reprehensible if the one doing it is truthful, and unlawful if he is a liar; because of the Prophet's (peace and blessings of Allah be upon him) saying: "Swearing makes a commodity marketable, but it deprives it of blessing." Buying from a seller who swears is permissible, but if a seller who does not swear is found, it is better to buy from him as a deterrent to the swearing seller.