What is the ruling on working as a sales representative with government agencies for a company that stipulates giving a gift or a sum of money to the purchasing officer, knowing that this is common practice in the market and that the company supports this action?

Bribes are forbidden, whether paid by the agent from his own money or by the company to him, due to the Prophet's curse upon the briber, the bribed, and the intermediary. Among the wisdoms behind its prohibition are that it corrupts morals and unjustly consumes people's wealth. This bad behavior must be combated by advising those who engage in it and alerting officials to put an end to it. There is no necessity to offer bribes, and whoever abandons something for the sake of Allah, Allah will compensate him with something better. The actions of agents in this regard are not to be taken into consideration, as customs that contradict Islamic law are invalid.