You're probably thinking of Jesus' promise to His disciples shortly before His death, telling them that soon He will be going to heaven to prepare a place for them. This is a wonderful promise, and it must have been very reassuring to them -- as it should be to us.
Jesus then added, "In my Father's house are many mansions; if it were not so, I would have told you" (John 14:2, KJV). Newer translations of the Bible use "dwelling places" or "rooms" to describe our heavenly home (which is what the old word "mansions" once meant in English). But either way, Jesus is assuring us that heaven is our final home -- and it will be glorious beyond description. More than that, there will be enough room for everyone who should be there.
I have often said that everything the Bible says about heaven should make us want to go there -- just as everything it says about hell should make us not want to go there. And we can know that heaven is our final home, by giving our lives to Jesus Christ and trusting Him alone for our salvation.
Is heaven your destiny? Do you know -- really know -- that if you were to die tonight, you would go to be with God forever in heaven? Don't live in doubt any longer, but open your heart to Christ and ask Him to take away your sins and save you. The Bible says, "For God so loved the world that he gave his only and only Son, that whoever believes in him shall not perish but have eternal life" (John 3:16).