Verse 2.1.4

स य एतदेवं विद्वानसाधु सामेत्युपास्तेऽभ्याशो ह यदेनं साधवो धर्मा आ च गच्छेयुरुप च नमेयुः ॥ २.१.४ ॥
॥ इति प्रथमः खण्डः ॥

sa ya etadevaṃ vidvānasādhu sāmetyupāste'bhyāśo ha yadenaṃ sādhavo dharmā ā ca gaccheyurupa ca nameyuḥ || 2.1.4 ||
|| iti prathamaḥ khaṇḍaḥ ||

4. If a person knows the Sāma as such and worships it with the awareness of the great qualities it possesses, those qualities very soon manifest themselves in him and become a source of happiness.

Word-for-word explanation:

Saḥ yaḥ, whoever; etat, this [Sāma]; evam vidvān, knows in this way; sādhu sāma iti upāste, [and] worships Sāma as ‘sādhu’; enam, to this worshipper; sādhavaḥ dharmāḥ, the good qualities that are associated with a perfect [sādhu] person; abhyāśaḥ ha, quickly; yat āgaccheyuḥ ca, come; upa ca nameyuḥ, and are a source of satisfaction. Iti prathamaḥ khaṇḍaḥ, here ends the first section.

Commentary:

First and foremost, a person should know the good qualities of the Sāma. But that is not enough. He should also worship the Sāma along with those good qualities. Then those qualities will soon manifest themselves in him, and they will eventually become a great source of satisfaction too.