“It just is,” is not an answer to the question; it is an opinion.
Neither is “My parents taught me.” Parents are an authority figure, but they do not define morality in any absolute way because they are humans whose opinions are subject to change. “The Bible says so,” is a legitimate answer because if you believe the Bible is God’s Word, then you want to obey God so you don’t fall into disfavor with a supreme being who controls your eternal destiny.
https://www.afa.net/the-stand/....faith/2021/05/you-ha