Yōga Sūtra 1.05

वृत्तयः पञ्चतय्यः क्लिष्टा अक्लिष्टाः।

vr̥ttayaḥ pañcatayyaḥ kliṣṭā akliṣṭāḥ।

[वृत्तयः पञ्चतय्यः क्लिष्टा अक्लिष्टाः।
vr̥ttayaḥ = activities are; pañcatayyaḥ = of five types; kliṣṭā = difficult; akliṣṭāḥ = not so difficult;]

Activities are of five types, subdivided into those that are difficult and not so difficult.

Activities are broadly classified into two categories, difficult and those that are not so difficult. Within them there are five types. Here activities that are difficult are those that are not pleasurable, which mind does not take readily to, and those that are not so difficult are activities that are pleasurable, which mind readily goes after.