Answering the question “I do not understand why Allah would give such a big punishment for such a small sin of taking a false oath in his name?”

Question : I do not understand why Allah would give such a big punishment for such a small sin of taking a false oath in his name?

The Prophet said, “(There are) three (types of persons to whom) Allah will neither speak to them on the Day of Resurrections, nor look at them (They are):–(1) a man who takes a false oath that he has been offered for a commodity a price greater than what he has actually been offered; (2) and a man who takes a false oath after the ‘Asr (prayer) in order to grab the property of a Muslim through it;……

[Ref: Saheeh Bukhari]

Answer : http://fahmalhadeeth.com/allah-not-speaking-nor-looking-at-those-who-bear-his-false-oath/