I bought the DVD of this movie today, what a real pleasure and a joy it is to become reacquainted with it. This clip, unfortunately without subtitles, is from after the Tartar raid when the church has been ransacked and desecrated. Rublev's dead icon master Theophanes returns to debate with him about whether there's any value to painting in the face of cruelty and death. Rublev decides to take a vow of perpetual silence and ceases to paint.
Listen out for Tarkovskys use of bells at the beginning, which brilliantly lend atmosphere and poignancy to the scene without a whiff of over emotionality or manipulation. The bells will not toll again until the great bell making scene at the end of the film.