言教不如身教

yánjiàobùrúshēnjiào
Explaining in words is not as good as teaching by example (idiom). Action speaks louder than words.

CEDICT

Entry Composition

1 言教 yánjiào to give verbal instruction
2 不如 bùrú
  1. not equal to; not as good as; inferior to
  2. it would be better to
3 身教 shēnjiào to teach by example