Bhagavad Gita · Raja Vidya Raja Guhya YogaChapter 9, Shloka 5 (9.5)

Shankaracharya — non-attachment. Paśya me yogaṃ yuktiṃ ghaṭanaṃ … ātmano yāthātmyam — my yoga, that is, the true nature of the self; śrutiḥ asaṃsargitvāt asaṅgatāṃ darśayati — "asaṅgo na hi sajjate" (Brihadaranyaka 3.9.26) — it is unattached, it does not cling; bhūta-bhṛt asaṅgo'pi san bhūtāni bibharti — though unattached, it sustains beings — that is the wonder. Saying "my self" is loka-buddhim anusaran — following ordinary ways of speaking.

Acharya Ramanuja — sustaining by will. Na ghaṭādīnāṃ jalādeḥ iva mama dhārakatvam, kathaṃ? mat-saṃkalpena — I do not hold things as a pot holds water; how then? by my will; sarveṣāṃ bhūtānāṃ bhartā ahaṃ na ca taiḥ kaścid api mama upakāraḥ; mama ātmā eva bhūta-bhāvanaḥ, mama mano-mayaḥ saṃkalpa eva bhūtānāṃ bhāvayitā dhārayitā niyantā ca — my will itself is what creates, sustains and governs all beings.

The difference: Shankara — the paradox of the unattached self (pure consciousness); Ramanuja — the power of will, which sustains everything without any physical contact.