Upvote:6
I am not sure, but it may be a reference to Hebrews 11:
13 All these people were still living by faith when they died. They did not receive the things promised; they only saw them and welcomed them from a distance, admitting that they were foreigners and strangers on earth. 14 People who say such things show that they are looking for a country of their own. 15 If they had been thinking of the country they had left, they would have had opportunity to return. 16 Instead, they were longing for a better countryβa heavenly one. Therefore God is not ashamed to be called their God, for he has prepared a city for them.
Also, Philippians 3:
20 But our citizenship is in heaven. And we eagerly await a Savior from there, the Lord Jesus Christ, 21 who, by the power that enables him to bring everything under his control, will transform our lowly bodies so that they will be like his glorious body.
For reference, I believe this is the C. S. Lewis quote you are referring to:
βThe Christian says, 'Creatures are not born with desires unless satisfaction for those desires exists. A baby feels hunger: well, there is such a thing as food. A duckling wants to swim: well, there is such a thing as water. Men feel sexual desire: well, there is such a thing as sex. If I find in myself a desire which no experience in this world can satisfy, the most probable explanation is that I was made for another world. If none of my earthly pleasures satisfy it, that does not prove that the universe is a fraud. Probably earthly pleasures were never meant to satisfy it, but only to arouse it, to suggest the real thing. If that is so, I must take care, on the one hand, never to despise, or to be unthankful for, these earthly blessings, and on the other, never to mistake them for the something else of which they are only a kind of copy, or echo, or mirage. I must keep alive in myself the desire for my true country, which I shall not find till after death; I must never let it get snowed under or turned aside; I must make it the main object of life to press on to that country and to help others to do the same.β