God has ordained government to establish rules and regulations for our lives. Jesus even established the precedent and showed the importance of paying taxes. Government today has established licensing in order to regulate and tax the citizens' activities. Government has established drivers' license, car registrations, fishing licenses, hunting licenses, permits to carry firearms concealed, etc. These are areas that our elected officials have deemed necessary in order to provide safety and order for the entire electorate. Two hundred years ago there were no drivers license or car registrations because there were, of course, no automobiles. It would have seemed outrageous to issue a license to everyone who fished or hunted in order to provide food for their families. These licenses became necessary as the populace grew.
Government also issues marriage licenses. These licenses allow the government to make sure that no one is manipulating others through deceit (ie. marrying multiple spouses) and to make sure no one is marrying a relative. However, Government did not create the institution of marriage. People have been getting married for over six thousand years.
Today, Government and culture are attempting to redefine what marriage is. Thus the spiritual issue: Government does not and never has defined what marriage is - God instituted and defined what marriage is. God created the bond and the role of marriage for mankind. (Genesis 2:24)
The parameters and institution of marriage were so important to God, that He used that same picture to show His relationship to the nation of Israel in the Old Testament (Isaiah 54:5-10) and the relationship of Jesus to the Church in the New Testament (Matthew 25:1-13). Christians know that the Bible tells us that in Heaven, during the Tribulation period, the Church will be presented to Jesus Christ as the 'Bride', there will be a marriage ceremony which will be followed by a marriage feast. God puts great emphasis on the institution of marriage. It is not for man to decided what a marriage is - it is from God.
Everyone will give account for his/her own actions before God someday (Romans 14:12). Exactly how foolish will one look standing before God and telling Him that we were aware of what his Holy Scriptures said about marriage, but we 'thought' and 'felt' our idea was better.