Is it a sin to do "works" for the sake of "rewards" in heaven? I was reading up on an article that was talking about rewards in heavens. Then it struck me, is it a sin to do "works" for the sake of "rewards" in heaven ?

What does the Bible have to say regarding doing works for the sake of rewards in heaven ?==
Side question: What is the difference between "seeking personal gain" and "selfish ambition" ?
I would have to say No.

Jesus said in Matthew 6:20 (NIV):


  But store up for yourselves treasures in heaven, where moths and vermin do not destroy, and where thieves do not break in and steal.


Here, he indicates that you should work towards heavenly treasures.

Furthermore, he encouraged here, in Matthew 19:21 (NIV)


  Jesus answered, “If you want to be perfect, go, sell your possessions and give to the poor, and you will have treasure in heaven. Then come, follow me.”


If you read the entire passage, the motivation for the rich man was to attain eternal life: “Teacher, what good thing must I do to get eternal life?” (Matthew 19:16).  The motivation was clearly selfish and self motivated.  However, Jesus did not respond saying that the motivation was wrong, but merely that his acts needed to be changed in order to gain treasures in heaven.

It's pretty clear that Jesus wants us to work towards heavenly treasures.



As sidran32 pointed out, while works will get you treasures in heaven, they will not provide salvation.  Of course, that's not what you asked, though, is it?