यस्मिन्यथा वर्तते यो मनुष्यः तस्मिंस्तथा वर्तितव्यं स धर्मः । मायाचारो मायया वर्तितव्यः साध्वाचारः साधुना प्रत्युदेयः ॥
One should behave toward another just as that person behaves toward them — this is considered true Dharma. A person who acts with deceit should be met with deceit, and a person who acts with goodness should be met with goodness.
dharmareciprocityethics