A man at the far end of the town—who knows that, if he were to go, he would not catch the Friday Prayer—performs the Zuhr Prayer before the imam leads the Friday Prayer. According to the apparent meaning of the author’s words, his prayer is not valid, due to the generality of his statement: “Whoever performs the Zuhr Prayer before the imam’s prayer.” That is, even if he knows that, were he to hasten there, he would not catch the Friday Prayer, he must wait until the imam has finished the Friday Prayer, and estimate its completion accordingly.

It was also said that he may perform the Zuhr Prayer if he knows that he will not catch the Friday Prayer, because in that case he is not required to go to it, and so there is no benefit in waiting.

“And it is valid when performed by one upon whom it is not obligatory ……”

His statement, “And it is valid when performed by one upon whom it is not obligatory,” means that the Zuhr Prayer is valid when performed by one upon whom the Friday Prayer is not obligatory, even if the imam has not yet prayed.

An example is a sick person whose illness exempts him from the Friday Prayer: if he performs the Zuhr Prayer before the imam leads the Friday Prayer, it is valid, because the Friday Prayer is not obligatory upon him.

Another example: