Is it necessary to have Bible authority for everything, one does, in religion?
Yes, Christianity is a religion of authority. Jesus said, "All authority hath been given unto me in heaven and on earth" (Matthew 28:18). Since Christ was given all authority, then all one does in religion must be authorized by him through his word revealed to one through the Bible.
The apostle Paul stated, "All scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness: that the man of God may be perfect, thoroughly furnished unto all good works" (II Timothy 3:16-17). The apostle Peter wrote, "According as his divine power hath given unto us all things that pertain unto life and godliness, through the knowledge of him that hath called us to glory and virtue" (II Peter 1:3). From these two passages of scripture, one can see that God has given to the human race, all they need to serve Him, according to His Divine will.
There are many accounts in the Old Testament where men disobeyed God, and were punished severely. In the book of Numbers 15:32-36 a man was found gathering sticks on the sabbath day. God told Moses that the man shall surely die, the people stoned him to death. Why did God command such punishment? Because he did not obey God's commandment. "Remember the sabbath day, to keep it holy" (Exodus 20:8), was God's command with additional instructions. The man took it upon himself to disobey God. We are not required to keep the sabbath today, but God still demands obedience under the New Testament law.
God has revealed what he wants in worship unto Him. He has warned about adding to or subtracting from His Holy Word. The following scriptures gives these warnings: Deuteronomy 4:2; Proverbs 30:6; Galatians 1:6-9 and Revelation 22:18,19. Many things that God commands of Christians, through His word, He doesn't give detailed instructions therefore, expediency would be used in carrying out the command. ---Charles E. Burch