I always find it helpful to read the context of Matthew 15:1-6 in understanding vv. 7-9.
Specifically, understanding the word Corban (rendered “gift” in the KJV and DRB), and how that was mis-used to exempt somebody of their 4th Commandment duties, really adds a huge depth of understanding to why Jesus took that specific moment to rant at the Pharisees. The utter hypocrisy they displayed would be maddening, wouldn’t it?
What makes it particularly interesting is if you take the time to understand the Torah and, if you can, the Babylonian Talmud, about the practice...