Highest Refuge
Ācārya-abhimānam — the Ācārya's deep affection (abhimāna: proud ownership, tender cherishing) for his disciple — is emphasized by Piḷḷai Lokācārya and Maṇavāḷa Māmunigaḷ as the ultimate upāya. When the Ācārya feels this toward a disciple, it is as if Bhagavān Himself has turned His grace toward that soul.
Scriptural Basis
Piḷḷai Lokācārya in Śrīvacana Bhūṣaṇam (cūrṇai 406 ff.) states explicitly that Ācārya-abhimānam is the supreme refuge — more accessible than direct bhakti or jñāna-yoga for most souls. The Carama Śloka is read as the Lord directing the soul to the Ācārya, who then enacts Bhagavān's redemptive will.
Practical Implication
A disciple who clings to the Ācārya's grace need not fear any obstacle. The Ācārya, who has realized the Lord, becomes the vessel through which divine grace flows unobstructed to the surrendered śiṣya.