Strong's Concordance G646

Act 21:21  And they are informed of thee, that thou teachest all the Jews which are among the Gentiles to forsakeG646 Moses, saying that they ought not to circumcise their children, neither to walk after the customs.

2Th 2:3  Let no man deceive you by any means: for that day shall not come, except there come a falling awayG646 first, and that man of sin be revealed, the son of perdition;