Part 7 of Sri Anandazhvan Vaibhavam written by Sri TCA Venkatesan [www.acharya.org]
A disciple of Ramanuja called Sri Echchan asked Anandazhvan “What does the acharya do for a sishya?”
Anandazhvan replied “The Jivatma is a girl and the acharya is the father of this girl. Through the mediation of Guru Parampara and chanting the Dvaya mantra, he offers this girl’s hand to her husband who is the Lord Sriman Narayana”.
This explains the handing of a disciple to the Lord by an acharya through the example of a father offering his daughter to his son-in-law by pouring water. Just as there are match makers for marriages of this world, the acharyas act as match makers for the marriage between the jIvAtmA and the paramAtma.
This concept is detailed in great length in the Acharya Hrudayam sutra “vidhyai thAyAgap peRRup … aNaiyum vasthuvukku maNivallip pEchchu vandhERiyanRu”. In Mumukshuppadi, Pillai Lokacharyar says “ettizhaiyAy mUnRu saradAy iruppadhoru mangala sUthram pOlE thirumanthram”.