Is it permissible to enter the mosque without ablution, and to use it as a passageway to reach the place of ablution and return from it?

Entering the mosque for one who has not performed ablution is permissible, as long as he is not in a state of ritual impurity (junub) or menstruation (ha'id). It is also permissible to pass through the mosque to reach the place of ablution if it is the only path, and for a legitimate purpose. However, passing in front of a praying person is not permissible due to the great sin involved therein.