Risālat al-Ḥuqūq
Hadith 38وحق الخليط أن لا تغره ولا تغشه ولا تخدعه وتتقي الله تبارك وتعالى في أمره.
The right of the associate (khalit) is that you neither mislead him, nor act dishonestly toward him, nor deceive him, and you fear God in his affair.