成唯識論述記 3.22

3.22

述曰：謂要長時，其性一類相續無斷，至得對治道，名「至究竟位」，各各究竟故。

The Commentary states: This means it must be for a prolonged duration, its nature belonging to a single continuous category without interruption, until the path of counteraction is attained; this is called 'reaching the ultimate stage', because each reaches its own culmination.