I'm going to ask other family members not to buy my kid clothes
Why don't you want your child to receive clothes?
I think they will be spoiled.
It is a natural motive that family members will want to buy clothes for your child. If you don't want them to do that, you should tell them and they should respect your decision.
I want my kids to earn respect , why can't other people see that?
Well an occasional gift isn't harmful. You should try to raise your kids to be polite and helpful, a treat now and then won't spoil them.