In plain words
But the Mahātmas, Partha, taking refuge in the divine nature, worship Me with undivided manas, knowing Me as the imperishable source of beings.
Word for word
But the great-souled, O son of Pṛthā, having taken refuge in the divine nature, worship Me with manas on no other, having known [Me as] the imperishable source of beings.
महात्मानस्तु मां पार्थ दैवीं प्रकृतिमाश्रिताःभजन्त्यनन्यमनसो ज्ञात्वा भूतादिमव्ययम्
Other commentaries
The commentators
▸Bhagavadgītābhāṣyam
ये पुनः श्रद्दधानाः भगवद्भक्तिलक्षणे मोक्षमार्गे प्रवृत्ताः —
महात्मानस्तु अक्षुद्रचित्ताः माम् ईश्वरं पार्थ दैवीं देवानां प्रकृतिं शमदमदयाश्रद्धादिलक्षणाम् आश्रिताः सन्तः भजन्ति सेवंते अनन्यमनसः अनन्यचित्ताः ज्ञात्वा भूतादिं भूतानां वियदादीनां प्राणिनां च आदिं कारणम् अव्ययम् ॥ १३ ॥
In plain words
But those who trust this, and who have set out on the road to freedom whose whole mark is devotion to the Lord —
But the great souls — and by great he means those whose minds are not small — take shelter in the divine nature, the nature the gods have: stillness, restraint, compassion, trust, and the rest of it. Standing there, they worship me, the Lord, Pārtha — worship meaning they serve me — with a mind that turns to no other, a thought that settles on nothing else. And they do it having known me as the origin of beings: the origin, the cause, of space and the elements that follow it and of every breathing creature — the cause that never wears away.
Close to the Sanskrit
But those who, having faith, are set out upon the path of liberation whose defining mark is devotion to the Lord —
But the great-souled ones — that is, those whose minds are not petty — having taken refuge in the divine nature, the nature of the gods, characterized by tranquility, restraint, compassion, faith and the rest, being such, worship, that is, serve, Me, the Lord, O Pārtha, with minds turned to no other, that is, with thought fixed on nothing else, having known Me as the origin of beings — the origin, the cause, of the elements beginning with space and of living creatures — the imperishable.