Question
If the worshiper forgets a complete pillar with the imam, should he repeat a unit after the prayer or is his prayer invalid?
Answer
I say, and with God's success: He must perform the pillar immediately, then complete his prayer for it to be valid. If he does not do so, he must perform a complete unit at the end of the prayer to make up for the one he missed due to neglecting the pillar. If he does not do this, his prayer is invalid. And God knows best.