The Substance -Colossians 2:16-20

Colossians 2:16-20 ESV
16 Therefore let no one pass judgment on you in questions of food and drink, or with regard to a festival or a new moon or a Sabbath. 17 These are a shadow of the things to come, but the substance belongs to Christ. 18 Let no one disqualify you, insisting on asceticism and worship of angels, going on in detail about visions, puffed up without reason by his sensuous mind, 19 and not holding fast to the Head, from whom the whole body, nourished and knit together through its joints and ligaments, grows with a growth that is from God.
20 If with Christ you died to the elemental spirits of the world, why, as if you were still alive in the world, do you submit to regulations—

The substance that we hold and makes our footing secure is Christ. He is the root and cause of all creation, and is the word of salvation for everyone. Not all would agree, but this does not take away from the fact it is true. Many will say there are other ways to God, or that there is no God. One can take this stand if one is unfamiliar with the Bible, or chooses to ignore what it tells us. Part of the endurance of the saints is holding on to the word of God, despite smooth and beguiling words to the contrary. The way of man and the way of God are not the same.
It's all too easy to find forbidden fruit in your hand. It's all to easy to listen to deceptive mouths, especially when one is hearing those words spoken in his own voice.

Hebrews 8:5-6
They serve a copy and shadow of the heavenly things. For when Moses was about to erect the tent, he was instructed by God, saying, “See that you make everything according to the pattern that was shown you on the mountain.” 6 But as it is, Christ has obtained a ministry that is as much more excellent than the old as the covenant he mediates is better, since it is enacted on better promises.

Hebrews 10:1
1 For since the law has but a shadow of the good things to come instead of the true form of these realities, it can never, by the same sacrifices that are continually offered every year, make perfect those who draw near.

Genesis 3:13
Then the Lord God said to the woman, “What is this that you have done?” The woman said, “The serpent deceived me, and I ate.”

1 Corinthians 9:24
24 Do you not know that in a race all the runners run, but only one gets the prize? Run in such a way as to get the prize.

Ephesians 4:15-16
Rather, speaking the truth in love, we are to grow up in every way into him who is the head, into Christ, 16 from whom the whole body, joined and held together by every joint with which it is equipped, when each part is working properly, makes the body grow so that it builds itself up in love.