The New John Gill Exposition of the Entire BibleJohn 6:59
These things said he in the synagogue…
publicly, in the place of divine worship, where the Jews resorted
for that purpose:
as he taught in Capernaum;
his own city, and where there was a
synagogue, into which he often went and taught his doctrines, and
wrought miracles; see (Matthew 3:13) (8:5,14) (9:1,2) (12:9) .