Sheikh Muhmamad b. Husayn al-Jîzânî, professor the Islamic University, Madinah
In Islamic legal methodology, juristic analogy (qiyâs) is used to determine the legal ruling for some new matter that is not directly addressed by the sacred texts. This is done buy comparing the new matter to another matter that already has a legal ruling specified for it by the sacred texts.
One of the essential conditions of a valid juristic analogy in is that the new matter whose ruling is being sought must be very similar to the old matter in Islamic Law it is being compared with.
The matter in Islamic Law whose ruling is established by the sacred texts should have some known quality about it that makes its legal ruling suitable for it. This quality must also exist in the new matter that we wish to compare with it. Otherwise, the new matter will be dissimilar and the analogy will be invalid. In Arabic, this is called (qiyâs ma` fâriq).
An example of a misplaced analogy is to compare obligatory acts with recommended ones or permissible ones. The same can be said for comparing things that are permissible or disliked with forbidden matters.
Another false analogy is to compare a thief’s liability for property that he has stolen to that of an honest person holding the property in trust.
And Allah knows best.
Source: Islam Today