Two-Bit Matthews is a loud-mouth jokester of a character. As such, he talks a lot. More often than not, he is cracking a joke or antagonizing Socs or fellow Greasers; therefore, he rarely says anything deeply meaningful. I can think of three times in the text that Two-Bit breaks this rule of thumb and says something that makes an impact on readers. Perhaps it is because he so rarely says anything profound that these three comments tend to strike readers in a way that calls specific attention to the quote. The first quote is something that Two-Bit says to Ponyboy about getting tough.
Ponyboy, listen, don't get tough. You're not like the rest of us and don't try to be...
It is an important quote because Two-Bit is a rough-and-tumble kind of guy. Being tough is what he does well and likes to do, but he recognizes that Ponyboy is not like that. Two-Bit sees what everybody else sees in Ponyboy: he is special and has a chance to do more with his life than be in a gang.
A second quote isn't as profound as the previous quote, but I think it alerts readers to the fact that Two-Bit has a very quick wit and isn't afraid to use it to pick a fight. He's fearless with his comments.
"Listen, greasers, we got four more of us in the back seat..."
"Then pity the back seat," Two-Bit said to the sky.
By far, Two-Bit's quote that carries the most weight is the following quote, because it shows that Two-Bit sees to the heart of issues despite joking about anything and everything. He recognizes that being a Greaser is holding certain members back.
You know, the only thing that keeps Darry from bein' a Soc is us.