I.5 - vṛttayaḥ pañcatayyaḥ kliṣṭaḥ akliṣṭāḥ

What is the mind? Pataïjali defines the mind through its activities. 

There are five activities of the mind. Each can are hurtful or non-hurtful.

Whether these acitivies are beneficial or hurtful cannot always be seen immediately. Time and space will determine their effects. The Sūtra also reminds us that in Yogic paradigm, mind can be both the source and solution to suffering.