The Galatians knew that they received salvation by faith. However, upon the influence of the Judaizers, they had started to think that maybe they needed to add to what Christ had done.
The just shall live by faith -- so Paul isn't saying that we shouldn't have good works, but that good works are not for the purpose of salvation. Good works are our response to the grace that God has already shown us by Christ's sacrifice.
"There is neither Jew nor Greek, there is neither slave nor free, there is neither male nor female – for all of you are one in Christ Jesus." (3:28) Here is the original human rights declaration. At the time Paul wrote this, it was normal to practice racism, slavery, and sexism. (Similar sentiments are expressed in Colossians 3:11.)
Many Malaysian Christians, like the society around us, are still racist. I know a lot of us complain about the racism shown against non-Malays, but many of us also show racism towards others. Even things like refusing to rent properties to people of the "wrong race", etc. and I can't count the number of times fellow Chinese-Malaysian Christians have said racist things against Indians and Malays.