Literally, “gnashed their teeth at him.” The figurative expression is not infrequent (Matt. 8:12; 13:42; etc.). Here, however, it is a literal manifestation of wrath. The Jews had allowed their rage to pass beyond control. Speechless with anger, they wanted to rend him as brute beasts would tear their prey with their teeth.
When they heard.
Rather, “Now while they were hearing.”
Cut to the heart.
See on ch. 5:33. The word used describes a keener pang than the “pricked” of ch. 2:37, and it produced now, not repentance, but furious wrath.