狗咬吕洞宾，不识好人心

狗咬吕洞宾，不识好人心

gǒu yǎo lǚ dòng bīn, bu shí hǎo​​ rén xīn

The goodness of a person is of no consequence to the ungrateful.

translation = "A dog biting Lu Dongbin / not being able to recognize a kind-hearted man"