Matthew chapters 5-7 may sound scary. But all Jesus is doing is elevating the law to its proper place to get His listeners to ask the question, “well who then can be saved?”
The answer is – no one can be saved by keeping the law, because no one can keep it perfectly. Thus, Jesus is getting them to start looking to the messiah (Him) for salvation, rather than by keeping the law (that they thought they were keeping perfectly).