Our Scripture reading today is Luke 10:19-20.
Verse 20, "Notwithstanding in this rejoice not, that the spirits are subject unto you; but rather rejoice, because your names are written in heaven."
It does not get much better than that on a Monday morning!  A reminder that as followers of Jesus Christ, our names are written in heaven and they cannot be erased.  I cannot think of a better reason to rejoice no matter what day of the week it is.  There isn't anything this world can offer that should cause us to rejoice more than knowing are names are written in heaven.  
The Apostle John writes in Revelation 20:15, "And whosoever was not found written in the book of life was cast into the lake of fire."  Here we find the why of our rejoicing.  By the mercy of God, we will not be cast into the lake of fire.  This is what we deserve, but God's mercy allows us to be redeemed by the blood Jesus Christ.  God is making sure that we rejoice more over what He freely gave us (salvation) than what we can do.  In other words, rejoice more over the eternal than over the temporal.    
Rejoice today that your name is written in Heaven!