Mahatmanas Tu Mam Partha

After the portrait of the deluded in 9.11-12, Krishna now paints the opposite picture. The mahatmas — great-souled ones — take shelter in daivi prakriti, the divine nature. They know Krishna as the imperishable source of all, and they worship him with undivided attention.

Undivided mind — ananya-manasah — does not mean thinking of nothing else every second of the day. It means that the fundamental direction of one's life points toward the divine. Like salt dissolved in water: you cannot separate them. The mind and its devotion become one.

Notice that Krishna does not say mahatmas are born special. They have 'taken shelter' of the divine nature — it is a choice, an orientation. Anyone can make that choice.

Shlokas 9.13 and 9.14 should be read together. Here, the inner quality of the mahatma is described — daivi prakriti and ananya bhava. In 9.14, their outward practice is described — kirtan, prananam, bhakti.

Gita 12.2 also uses the term 'ananya-chetah' — one whose mind does not wander elsewhere. Krishna considers such devotees the highest among yogis. Shloka 9.13 lays the groundwork for that later declaration.