“If you died with Christ from the elements of the world, why, as though living in the world, do you subject yourselves to ordinances,”
The reasoning here in this verse is clear. If we are part of the spiritual body of Christ, and are set apart from the elements that features in this world, why would we insist on continuing on with the outward, fleshly ceremonies that are now defunct. They are unnecessary, as the Lord Jesus has come and is revealed to His people, who follow Him with redeemed hearts and minds and are alive in their souls. The elements and essential components of this vain world are not the motivation of the Christian any more. Our inner eye has been changed and we see and desire the spiritual portion of God. Our hearts are now set after God and His will and our minds are being conformed to the mind of Christ.
When a person comes to faith in Christ, they die to the things of this life. Their soul has come alive to God and their desires change from being in thrall to this world, to loving the Lord God with all their heart and mind and strength. They cease from chasing the preoccupations of this life and start to live a new life in God. It changes all the priorities from the physical to the spiritual.
The ceremonies and ordinances of the Old Testament era were given to point to the living Saviour that would come to call out His people to respond in repentance and faith in Him. They were pictures and types of the real Lord and not a means in themselves. The believing Israelites would realise this and trust in God in faith just as we do now. They looked forward to the coming Messiah who would release them from the sin and death under which they lived, and set them free to serve God as He would command. So we also look to the Messiah who has come and has saved us from sin and given us faith to believe.
It is illogical to look back to days of shadow, when the Lord has already come and all the prophecies have been fulfilled and all the pictures have become reality. We serve the living Lord Jesus and have the revelation of His person in the Scripture, so why would we go backwards to the replaced pictures? The Christian is dead to the elements of this life and lives for another life in Christ, alive in soul to spiritual elements and God-orientated living. The Apostle seems incredulous that a Christian would seek to return to shadows rather than enter into the light of the gospel reality. We put off the now out of date ways and put on the new and living way of life in Jesus Christ the only Saviour. Anything else is just worldly mindedness.