But six times in the Sermon on the Mount, he introduced what sounded like statements from the Hebrew Scriptures with the words: “It was said.” (Matthew 5:21, 27, 31, 33, 38, 43) Why? Because he was referring to the Scriptures as interpreted in the light of Pharisaic traditions that contradicted God’s commandments. (Deuteronomy 4:2; Matthew 15:3)

16. What Jewish practice made the swearing of oaths meaningless, and what position did Jesus take?

¹⁶ In a similar vein, Jesus continued: “Again you heard that it was said to those of ancient times, ‘You must not swear without performing’ . . . However, I say to you: Do not swear at all.” By this time the Jews were abusing oath-taking and were swearing many oaths about trivial things without performing. But Jesus said: “Do not swear at all . . . Just let your word Yes mean Yes, your No, No.” His rule was simple: Be truthful at all times, not having to guarantee your word by an oath. Reserve oaths for vital matters.​—Matthew 5:33-37; compare 23:16-22.