Sure but did God tell you to buy groceries from a grocery store? Probably not. Did God tell you to use a computer to get online and join a forum? Probably not. There are many things God did not tell you to do in the bible that we must do today. Times have changed and we must change with them. In a good way and Godly way of course.
Totally disagree as we are talking about holy days and the observance of what they are from a Biblical perspective. They had markets and they traded also in their day. This is totally off point. As obviously there are day to day things they all did and we do that are not recorded in His word. We are talking about the observance and worship of God. That is so Greek thinking and philosophical. If you need to approach your walk with Yahweh from that perspective and to try and justify your actions with that philosophy well I am sorry.
How about, we may not fully understand the why or the how, but for me it is good enough that "because Yahweh said so" I don't need to fully understand the why! I believe He has my full interest at heart and only wants the very best for me in all areas of my life. Now I don't fully understand why He teaches us to worship Him the way He states in His word which is from Gen through to Rev. It never contradicts itself and Yahweh never changes. But Yahweh declares that if I do all will go well for me and I will live a happy peaceful life.
This is opposite to what I am seeing how the world is and to be honest most of Christianity because of the very thing that is being discussed in this thread. Many people are doing things in the name of Yahweh that He never instructed us to do. They are learning from the pagans and nations and trying to worship Yahweh that way when Yahweh clearly teaches not to learn their ways. Yahweh's word not mine. Yahweh does not change, Yeshua is the same yesterday, today and forever.
Shalom