As long as it is day, we must do the work of him who sent me. John 9:4
Jesus was telling his disciples these words to encourage them (and to encourage us) to do the work of God the Father while we have the time. For us, right now as we live, it is daytime and we work during the day, while we can see.
What do we do? We proclaim God's love to all people. We tell them that Jesus has died for their sins, that he has redeemed them and given them life in the face of death. After all, it is daytime for people who don't know God as well. It is daytime in the sense they are living now and now is their time of grace. For them, night will come and their time of grace will be over. This gives us a sense of urgency, doesn't it?
So now that we know what to do, we might ask why we do it. The reason is because we can't help it. We know that we are saved by God's grace in Jesus Christ. We know that we were rescued from death because God loves us. We know this and we praise God for this. We want others to know it as well and to praise him for his grace.
Therefore, we work while it is day. That is why we have been placed on this earth, to proclaim God's name and to worship him always.
