Veil, a Biblical teaching
It is a duty for those who serve God to wear the proper clothes for regular worship services. God teaches us that we must have a godly mind, and a man should not cover his head while a woman should cover her head.
… the head of the woman is man, and the head of Christ is God. Every man who prays or prophesies with his head covered dishonors his head. And every woman who prays or prophesies with her head uncovered dishonors her head—it is just as though her head were shaved.1 Co 11:3–5
The purpose of our having worship is to display the glory of God. Male members of the Church of God do not put anything on their heads to display the glory of God and female members put veils on their heads during worship as the Bible teaches. Female members wear veils because God gave the regulation as a sign of authority on their heads. Therefore, we must not regard any regulation as trivial or neglect it. There is nothing meaningless among the regulations of God. Every regulation is given for us to receive salvation and enter the kingdom of heaven.