Be fulfilled: see comment at 1.22.

That it must be so and “which say that this is what must happen” (Good News Translation) are both unclear as regards the intended antecedent. Phillips is better: “which say that all this must take place.”

Good News Translation expresses very well the intention of Jesus’ question. But how then is a short way of saying “But if God did that” or “But if God sent angels to protect me.” In some languages the meaning of the rhetorical question is expressed as a statement: “But if that happened, the Scriptures that say this must happen could not come true.”

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 .