If someone were to describe Ching, we wouldn't be surprised if they said he was like a brown paper bag. He's good at what he does, and he can do lots of things, but in the end he's just kind of boring. Wang Lung's nearest neighbor is the kind of guy you might not notice even if he's standing right in front of you.
That's because he doesn't have one thing that Wang Lung has in spades.
Ching has no moxie. No spunk, nothing. In a way, he kind of reminds us of O-lan; he's "[…] a small, quiet man, ever unwilling to speak unless he were compelled to it" (1.159). But even though O-lan is quiet, we don't think she'd ever be described as, say, "less than the shadow of a human creature" (9.11). Wow. He's not just a shadow; he's less than a shadow. That's got to hurt.
When Ching is compared to Wang Lung, it's easy to see how Wang Lung's life could have been very different if it weren't for his ambition. When Wang Lung decides to go to the South, Ching is too scared and stays home. While Wang Lung comes back from the South with a bag full of jewels, Ching loses his daughter and his wife to the famine.
This interaction kind of says it all: "Now Ching was a fearful and timid man and however bad the times were he did not dare as Wang Lung did to exclaim against Heaven. He only said "Heaven wills it," and he accepted flood and drought with meekness. Not so Wang Lung" (27.8). Ching will just accept what's given to him, but Wang Lung won't.
That's an important thing to remember. It can be easy to get on Wang Lung's back and start criticizing him for all his shortcomings—he certainly does have them. But what makes him interesting is his drive to become better, to make something of his life, to not just sit back and take whatever fate doles out. Ching's role is partly to show what happens to someone in Wang Lung's situation who doesn't have that kind of drive.
Ching is nothing if not loyal, and he expresses his loyalty by working. Hard. Even when he's old, he watches everything that goes on: you can't get a single grain of rice past him. Like other good qualities taken to extremes, this leads to problems. Or, specifically, to one problem: Ching dies because he's worked himself to death (29.66).
Now, that does show a certain kind of drive, but it doesn't show a lot of imagination. Wang Lung's drive is for dreams of the future; Ching's drive is to express loyalty.
Ching and Wang Lung become connected because of an exchange. When Wang Lung's uncle is spreading rumors, Ching is one of the only people who feel guilty about stealing stuff from Wang Lung's house. Later, he returns the very beans that he stole to Wang Lung so that O-lan can eat them and stay alive. When the family returns from the South, Wang Lung repays the favor by taking Ching under his roof.
It's then that their bromance blossoms. “And it seemed that the handful of peas and of seed which had passed between these two men made them brothers, except that Wang Lung, who was the younger, took the place of the elder, and Ching never wholly forgot that he was hired and lived in a house which belonged to another" (17.19). Okay, so there's one hitch in their love connection, but they're still bros, and their brohood has been established by the fact that they've each saved the life of the other (or of the other's loved ones).
Actually it's more than a little hitch, because that inequality leads to awkward moments like this: "'And if my poor girl were here and sound you might have her for nothing at all and my gratitude, too, but where she is I do not know, and it may be she is dead and I do not know. ‘Then Wang Lung thanked him, but he forebore to say what was in his heart, that for his son there must be one far higher than the daughter of such an one as Ching, who although a good man was, besides that, only a common farmer on another's land"(22.22).
Wait, is Wang Lung seriously pulling the you're-my-best-friend-but-you're-not-quite-as-rich-as-I-am-so-I-couldn't-really-let-your-kid-marry-mine card? Lame. Seriously lame. It's all the more remarkable that Ching remains so loyal in the face of this kind of total lameness from Wang Lung. It also shows that Wang Lung has a habit of treating good people badly. O-lan, anyone?
So when Ching dies, it's actually kind of surprising to see how sad Wang Lung gets. Out of all the deaths in the novel, it might be Ching's that hits him the hardest. Even though Ching's not family, Wang Lung makes his kids mourn him as if he is, and for three full days (29.75). Even though their relationship wasn't equal, Ching was the person Wang Lung trusted most, and he was the only person Wang Lung could trust, aside from O-lan.
We guess Wang Lung didn't realize that until Ching died. It's easy to think you've made it all on your own, but chances are you've got people like Ching and O-lan to thank for helping you get where you are. Wang Lung realizes too late how badly he's treated them... and now he's all alone.
Ching and O-lan are the trustworthiest people in the whole novel. They don't say much, but they work hard, and they're honest. They're also the foundation that Wang Lung builds his wealth on. O-lan runs the house, and she's the one who gets him the jewels to buy the land of the House of Hwang. Ching runs the farm and makes sure that no one tries to cheat Wang Lung.
These two should have been the most important people in Wang Lung's life, but they weren't. Both of them died unappreciated. Wang Lung didn't realize the importance of either of them until after they died. Maybe Wang Lung would have like them better if they had been prettier, like Lotus?