If the rapture takes place right after the seven years of the Great Tribulation, then we would know the return of Jesus Christ. And we understand that the Scripture says no one can know. Why would a believer stay alert if we knew when He was coming? But, the passages make it clear that since we don’t know, all believers must be in constant readiness for the rapture. That means that Christians have to be busy doing His will and living a life of righteousness and not in sin.