'Happened' in the Bible

"'When a person sins in that he hears a public curse against one who fails to testify and he is a witness (he either saw or knew what had happened) and he does not make it known, then he will bear his punishment for iniquity.

But Aaron spoke to Moses, "See here! Just today they presented their sin offering and their burnt offering before the Lord and such things as these have happened to me! If I had eaten a sin offering today would the Lord have been pleased?"