背道而驰

Origin and story

The Ministry of Education dictionary cautiously connects this idiom with Bai Juyi's Tang letter Wei Ren Shang Zaixiang Shu (為人上宰相書). Bai contrasts ministers who accepted responsibility for rescuing the state with those chiefly concerned to avoid danger themselves. He describes conduct that runs away from the proper path, rather than narrating a literal journey.

The dictionary treats the derivation as possible, not certain. The modern wording vividly turns opposed intentions or practices into travelers speeding in contrary directions. Thus it can describe behavior that contradicts a stated aim or two policies moving in opposite directions. It need not mean that both sides are morally wrong.