The rule of ugliness of punishment without expressing the law (qāʿida qubḥ ʿiqāb bilā bayān) and principle of precaution are the two central principles applied to something when one doubts whether that thing is prohibited or not. The application of the two principles comes after careful examination and despair of any evidence.
It is very clear that the result of each one is in clear conflict with the other because the result of the rule of "the ugliness of punishment without expressing the law" is to give preference to the rights of people in the sense that one is free from obligation, whereas the result of the principle of precaution is to give preference to the rights of God in the sense that it is obligatory to abide by what is likely to be the obligation. Given the domain of the application of these two principles and the practical and theoretical benefits of the two, it is necessary to discuss ways to resolve the conflict.
This article claims to give priority to the rights of God over the rights of people. In this regard, after preliminary discussions, six arguments have been presented and criticized about qāʿida qubḥ ʿiqāb bilā bayān, and finally it was concluded that, first of all, qāʿida qubḥ ʿiqāb bilā bayān is a rational rule and can be restricted. Secondly, this rule is specific to usual and customary masters (mawālī), not real master. So, when it is likely that Allah Almighty might have instructed us to do something, we must exercise precaution to make sure about it instead of considering ourselves relieved from obligation.