Fix your mind on Me alone, establish your intellect in Me. Then you will live in Me, without doubt, from here onward.

Direct instruction for devotional practice:

Mayi eva manaḥ ādhatsva — Fix (ādhatsva) the mind (manas) on Me alone (mayi eva). Mental concentration on the Divine.

Mayi buddhiṃ niveśaya — Establish the intellect (buddhi) in Me. Not only the emotional aspect but also the discriminative.

Nivasiṣyasi mayi eva — You will live in Me. Nivāsa is residence, dwelling. The union is not episodic but permanent.

Ata ūrdhvam — From here onward, from now upward/forward.

Na saṃśayaḥ — Without doubt. Kṛṣṇa guarantees the result.

This verse initiates a descending progression: if you cannot fix the mind, practice yoga (v.9); if you cannot practice, act for Me (v.10); if not even that, renounce the fruits (v.11).

Each level is valid; grace finds the way. But the ideal goal is this: mind and intellect absorbed in the Divine.