John 6:59
“These things said He in the synagogue, as He taught in Capernaum.”
2. The place where most of His marvels had been done, so that He ought there especially to have been listened to. But wherefore taught He in the synagogue and in the Temple? As well because He desired to catch the greatest number of them, as because He desired to show that He was not opposed to the Father.
Source: Homilies on the Gospel of John (New Advent)