Matthew 15:9

And in vain they worship Me, Teaching as doctrines the commandments of men.' " Matthew 15:9

Three points:

1. Worship

It is interesting that they WERE worshiping. BUT all their worship was in vain; it was not accepted by God, because it was not true worship. Proverbs 30:5 Every word of God is pure: he is a shield to them that put their trust in him. Since every word is true, we need to worship God the way He has instructed us. Isaiah 58:1-7. The problem is we may have the right form, but the wrong reasons.
"Cry aloud, do not spare, lift up your voice like a trumpet, and declare to my people their disobedience, and to the house of Jacob their sins. Yet they seek me daily, and delight to know my ways: as a nation that did righteousness, and did not forsake the ordinance of their God, they ask of me righteous judgments; they delight to draw near to God. 'Why have we fasted,' say they, 'and you do not see? Why have we afflicted our soul, and you take no knowledge?'"Behold, in the day of your fast you find pleasure, and exact all your labors. Behold, you fast for strife and contention, and to strike with the fist of wickedness: you do not fast this day so as to make your voice to be heard on high. Is such the fast that I have chosen? the day for a man to afflict his soul? Is it to bow down his head as a rush, and to spread sackcloth and ashes under him? Will you call this a fast, and an acceptable day to the Lord? "Isn't this the fast that I have chosen: to release the bonds of wickedness, to undo the bands of the yoke, and to let the oppressed go free, and that you break every yoke? Isn't it to distribute your bread to the hungry, and that you bring the poor who are cast out to your house? When you see the naked, that you cover him; and that you not hide yourself from your own flesh?

2. Teaching

We are commanded to teach. How else do we learn? We can teach by word, example, sharing experiences, etc, but something is wrong when we teach error. James 3:1 My brethren, be not many teachers, knowing that we shall receive greater condemnation.

3. Commandments of men

You know about the Ten Commandments. Those are right and true. Jesus himself said, (Matthew 11:29) "Take my yoke upon you, and learn of me; for I am meek and lowly in heart, and ye shall find rest to your souls." How different the commandments of men with their long lists and impossible demands. Let us be safe in the rules that Jesus gave us in the New Testament.