All weddings must have vows, and civil marriages are no different. Although in a civil marriage, the Church and God are not given pride of place, the couple still must make certain commitments in front of a government official that are considered binding verbal agreements just like any other contract. This pledge is probably more important than any other promise an individual might make in his/her lifetime. That’s because the vows made during the wedding are in effect for the rest of a person’s natural born life, and must be upheld throughout their everyday affairs, which is not common with other agreements.
The civil part of the vows is the legal part. You are declaring before witnesses that there is no legal reason why you cannot marry the other person (such as already being married to someone else) and that you are choosing the other person to legally become your spouse. It has to take place in front of an authorised person, usually someone legalised by that country. It provides protection for the spouses in case of death or divorce, when issues regarding property may arise.