Jesus said: "the harvest is plentiful, but the laborers are few." We are all called to be laborers in the harvest of salvation. Therefore it is important to stay awake! We shouldn't be sleeping when the harvest needs to be reaped by doing evangelism.
This is a clip from the full sermon 'The Two Harvests'. Full video: https://youtu.be/-hdDQu2Y2pE
4338, recorded in Westminster Chapel, London, September 29 1990