Now, the main reason why the godly man hath his heart thus to heaven, is because God is there; that is the palace of the Most High. It is the place where God is gloriously present, where his love is gloriously manifested, where the godly may be with him, and see him as he is, and love, serve, praise, and enjoy him perfectly. If God and Christ were not in heaven, he would not be so earnest in seeking it, nor would he take so much pains in a laborious travel through this wilderness, nor would the consideration that he is going to heaven when he dies, be such a comfort to him under toils and afflictions. The martyrs [would not cheerfully suffer so much], were it not that they hope to be with their glorious Redeemer and heavenly Father [in heaven]. The believer’s heart is in heaven, because his treasure is there.
Jonathan Edwards, Sermon on Psalm 73:25, “The Best Portion”