<b>Guidance from the Hadith:</b><br> 1) It is not permissible to embark upon or complete a supererogatory prayer after Iqāmah has been pronounced for an obligatory one, for the obligatory takes precedence over the voluntary.<br> 2) A person with proper understanding would prioritize acts of worship if they came at the same time.<br> <br> <b>Benefit:</b><br> If Iqāmah for prayer is proclaimed while you are in a supererogatory prayer, cut the prayer if you are still in the first Rak‘ah (unit of prayer). But if you are in the latter part of the prayer, like Tashahhud, then complete it quickly. To cut the prayer, get out of it without Taslim (salutation of peace ending the prayer), for Taslim is to be made after Tashahhud, and Allah knows best.