What does the Bible say in regard to getting married by elopement or quick marriage in a courthouse and then doing a renewal of the vows at a later date?
The Bible says nothing at all about the place (church or courthouse) or officiant (pastor or judge) for the establishment of a marriage. This is fully in the realm of Christian freedom and therefore subject only to Christian love, wisdom and discernment, and a concern for how other believers might perceive it (in case the weak might stumble spiritually and misunderstand). Marriage is really a civil matter, but Christians usually want to have the Word of God and prayer prominent at the occasion. So clergy (authorized by the civil authorities to perform weddings) and churches serve them.
The mention of elopement and civil weddings often causes the subject of motives and circumstances to surface. These deserve the attention of every bride and groom and their respective families. Are they avoiding church and God’s Word for a particular reason? Are they honoring their parents or hiding something from them? These and other similar questions are deserving of attention. But assuming that Christian faith, hope, and love are present and accounted for, civil marriages are just fine. And a later “consecration of civil marriage” can be done and will likely be appreciated by all Christians involved.