Is looking at a poor person with an element of sarcasm considered disbelief?

Mocking people is dispraised in Islamic law, and Allah has forbidden it in His saying: "O you who have believed, let not a people ridicule [another] people; perhaps they may be better than them." Mockery is not disbelief, but it is a sin for which repentance is obligatory. One should beware of indulging in intrusive thoughts regarding this matter.