Matthew 24:42 Watch therefore, for you do not know what hour your Lord is coming.
Just as we need to watch out for the evil people and things in this world, we also have to watch out for the promises God has made to us.
He has promised Christ will return some day and we have to be sure we are in a fit state for that to happen.
Jesus was always looking out for other people and always in communion with God; we need to take a leaf from His book and apply that in our lives.