Mantra 4

इन्द्रियाणि हयानाहुर्विषयाꣳस्तेषु गोचरान् ।आत्मेन्द्रियमनोयुक्तं भोक्तेत्याहुर्मनीषिणः ॥ ४ ॥

In plain words

The senses, they say, are the horses; the objects [of sense] are the paths on which they range. Ātman joined with the senses and manas — the wise call this joined complex the enjoyer.