Luke 12:56

Ye hypocrites, ye can discern the face of the sky and of the earth; but how is it that ye do not discern this time?

People were able to read the face of the sky and of the earth to predict the weather, yet they did not discern the time in which they were living. The signs of that time pointed clearly to Christ's mission and the coming kingdom of God. That failure showed ignorance and indifference, and it is rebuked as hypocrisy.

Those blessed with great light are accountable to discern the time. Tame, listless striving without religious interest is rebuked. The whole heart is to be put into the service of Christ in daily prayer and watchfulness. The chapter containing the verse is an important lesson for God's people.