What is the two-part allegorical saying with the answer to hitting people?

The anvil of the blacksmith's shop-the goods born to be beaten.

Rusty anvil needs beating.

Tell another joke I owe:

There was a rich man's son who was ignorant. After Xue finished teaching, let him write a poem and do exercises. After returning home, the master scratched his head and tossed around until midnight, saying nothing. He can't write it himself, and of course, the tangled servant is on pins and needles. One minute he asked the servant to take Mencius out and let him bring a birdcage to enlighten him. As a result, he accidentally let the bird fly out of the cage and made a noise in the middle of the night to catch the bird. He just got back to his desk because he couldn't sit still because of the quarrel next door. Later, I finally made up a song about that night's tossing, "Three hundred flies on the beam, walking under the light, two kings next door, husband and wife fighting all night." The bird bought with 320 silver flew to the beam, and I still insisted on reading Mencius' Zhang Wan under the lamp. What I can't decide in the end is that there is one more word in the fourth sentence, so I have no choice but to hand it in like this. Mr. Xue circled the last word after reading it.

A year later, the master overreached himself and went to Beijing to take the exam. He handed in this 20-word poem above the examination room. After reading it, the examiner can't help laughing, but after studying for so many years, he is so proficient and overreaching, which is really an insult to poetry. He criticized "I owe it!" . I didn't expect this paper to be known by the owner, so I went back to settle accounts with Mr. Xue: a good poem was changed by Mr. Xue, but it was not accepted because the word "big" was missing!