Deuteronomy 7:5 King James Version (KJV)
5 But thus shall ye deal with them; ye shall destroy their altars, and break down their images, and cut down their groves, and burn their graven images with fire.
Two ways to approach celebrating man-made “holy” days:
unbiblical way-you can celebrate anything so long as God does not forbid it in His Word (yet, He does forbid paganism mixed in with the holy worship of Him!)
biblical way-you can only celebrate that which is found in God’s Word and only in the way that is according to His Word