He who swears can be expressed as “the person who swears” or “anyone who swears.”

In light of Jewish teaching regarding “the lesser and the greater,” Jesus’ conclusion is easily understood. Since the altar is greater than the gifts that are on it, then whoever swears by the altar is swearing by those gifts as well. And by everything on it may also be translated “and by all the gifts which people have placed on it.”

Quoted with permission from Newman, Barclay M. and Stine, Philip C. A Handbook on the Gospel of Matthew. (UBS Handbook Series). New York: UBS, 1988. For this and other handbooks for translators see here .