Akvan sadi: “If there is a method leading to nibbana it has to start with listening and comprehending the sa-dhamma, as one does not have the ability to comprehend the sa-dhamma by himself…”.
That is correct.
Just to point out “sa-dhamma” is really “sath-dhamma” (or correct dhamma), which rhymes as “saddhamma” and thus is called “saddhamma“; see, “Saddhamma Sutta (AN 10.191) AND Saddhamma Sutta (AN 10.147)” in the post: “Dasa Akusala/Dasa Kusala – Basis of Buddha Dhamma“.
One of the requirements for Sotapanna phala is “listening to saddhamma” by an Ariya or a Noble person.