In theory, at least, we are more secure locked in. Prudence dictates that we lock in and lock out, lock up and lock down, Kryptonite and a hot line to the police station. But other doors get locked too. We secure the doors of our hearts and minds against those who are different from us. Fear locks the door and hangs out the cave canem.
Hospitality is suppressed.
No foreigners, heretics, enemies, sinners, unbelievers, misfits, or apostates need knock. If I let you into my life, there is no telling how God might ask me to change. Locked door no obstacle, Jesus comes and stands among them to reclaim and restore those who ran away, those who denied, those who deserted, those who could not stay awake, and those complicit in crucifixion. Peace be with you. He breathes on them.