Then many of the Jews which came to Mary, and had seen the things which Jesus did, believed on him.
Then many (or, 'Many therefore') of the Jews which came (or 'had come') to Mary (as sympathizing friends), and had seen the things which Jesus did, believed on him. These were of the candid class, on whom the effect of so stupendous a miracle, done before their own eyes, could not but be resistless. See the notes at John 12:9-11.