Remember therefore how thou hast received and heard, and hold fast, and repent. If therefore thou shalt not watch, I will come on thee as a thief, and thou shalt not know what hour I will come upon thee. (Revelation 3:3)This Christ’s counsel to the church in Sardis after He tells them to strengthen those ready to be martyred.
That phrase “If therefore thou shalt not watch, I will come on thee as a thief” tells how the sudden requirements the Lord asks of us can feel like He is stealing something from us if we are not watchful and ready to comply. This means that at no point can we allow ourselves to get too comfortable and complacent with our plans and our lives because at some point, the call comes to place that comfort on the altar and it is much harder to do if we aren’t watching.
For the church in Sardis, if they were too comfortable, then any sudden change that required their death to seal their testimony would seem as if the Lord had come to steal their peace and their lives.