…but ourselves also, which have the firstfruits of the Spirit, even we ourselves groan within ourselves, waiting for the adoption, to wit, the redemption of our body. – Romans 8:23

When the soldiers of Godfrey of Bouillon came in sight of Jerusalem, it is said they shouted for joy at the sight of the holy city. For that very reason they began to groan. Ask ye why? It was because they longed to enter it. Having once looked upon the city of David, they longed to carry the holy city by storm, to overthrow the crescent, and place the cross in its place. He who has never seen the New Jerusalem, has never clapped his hands with holy ecstasy, he has never sighed with the unutterable longing which is expressed in words like these-

“O my sweet home, Jerusalem,
Would God I were in thee!
Would God my woes were at an end,
Thy joys that I might see!”

An exile, far away from his native country, has been long forgotten, but on a sudden a vessel brings him the pardon of his monarch, and presents from his friends who have called him to remembrance. As he turns over each of these love-tokens, and as he reads the words of his reconciled prince, he asks “When will the vessel sail to take me back to my native shore?” If the vessel tarries, he groans over the delay; and if the voyage be tedious, and adverse winds blow back the barque from the white cliffs of Albion, his thirst for his own sweet land compels him to groan…So, you see, beloved, that because we have the “first-fruits of the Spirit,” for that very reason, if for no other, we cannot help but groan for that blissful period which is called “the adoption, to wit, the redemption of the body.” ~ C.H. Spurgeon

https://www.blueletterbible.org/Comm/spurgeon_charles/sermons/0788.cfm