The Bible teaches that sex was intended for marriage.

Marriage should be honored by all, and the marriage bed kept pure, for God will judge the adulterer and all the sexually immoral. (Hebrews 13:4, NIV)

Why should a couple wait until they are legally married?

1. Waiting demonstrates to each other, by your own actions, that you respect God's plan.

2. Waiting demonstrates to each other, by your own actions, that you can be trusted.  A couple who waits will have trust for each other from day one of their marriage.

3. Waiting demonstrates to each other, by your own actions, that your respect each other.