Is one who pays a bribe on behalf of his manager sinful, and is his money unlawful, and should he leave the job or continue in it?

Bribery is one of the major sins, and it is forbidden to engage in it for the briber, the bribee, and the intermediary if it leads the person to something they are not entitled to. As for bribery used to obtain a right or to ward off injustice, it is permissible according to the majority of scholars, and the sin in this case falls solely on the bribee. If the bribe was forbidden for you as the briber, then you must seek forgiveness, and this does not affect the lawfulness of your salary as long as your work is permissible. However, if the bribe was forbidden for the recipient but not for the giver, then there is no blame upon you.