What is the ruling on performing the Prayer of Fear (Salat al-Khawf) when there is no actual fear?

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If a congregation performs the Prayer of Fear without any actual fear present, the prayer of the Imam and the followers is invalid. This is because it involves leaving the Imam without excuse, or failing to follow the Imam in three pillars, or curtailing the prayer while the Imam completes it, all of which invalidate the prayer, with some difference of opinion regarding leaving the Imam without excuse. If the followers' prayer is invalid, the Imam's prayer is also invalid because he led those whose prayer is void, unless he leads them in two complete prayers, in which case his prayer, the first group's prayer, and the second group's prayer, which is built upon following a voluntary performer by an obligatory performer, are valid. The permissibility of following an obligatory prayer with a voluntary one has been affirmed.