He was also a rabbi of Beth El Congregation in Baltimore, Maryland, and a promoter of interfaith communication, which he referred to as "dialogue" or "trialogue".

He remained in Argentina for two months, then traveled to Brazil where he spent two weeks lecturing under the auspices of the American Jewish Committee and the Brazilian Institute for Culture and Information.

Professor Steven Katz described him as "a remarkable American Rabbi and scholar, illuminating Agus' commitment to Jewish people everywhere, his profound and unwavering spirituality, his continual reminders of the very real dangers of pseudo-Messianism and misplaced romantic zeal, and his willingness to take politically and religiously unpopular stands.

The people Israel are like the sun; the Christian community was the effluence of Divine rays permeating the nations with the spirit of monotheism.

The boundary line between Judaism and Christianity was not along the plane of intellectual thought, since the divine being could only be caught figuratively or symbolically within the meshes of human reason.