”I consider myself spiritual rather than religious. Why isn’t that enough?”
Because God loves you and wants even better things for you.
When people say they are spiritual rather than religious, they frequently mean that, although they don’t practice a specific religion, they recognize there is more to the world than matter; that it has a spiritual dimension.
This is good! But it doesn’t go very far. Wouldn’t it be nice to know more about the world’s spiritual dimension? In every field, having more knowledge is better, and it makes sense to ask if we can learn more about the world’s spiritual dimension.
From a Christian perspective, we can learn more. God loves us and wants us to know him, not just have feelings or guesses. When he created the universe, God left evidence that allows us to learn certain things about him: “Ever since the creation of the world his invisible nature, namely, his eternal power and deity, has been clearly perceived in the things that have been made” (Rom. 1:20).
He also left evidence in the human heart: “With [man’s] openness to truth and beauty, his sense of moral goodness, his freedom and the voice of his conscience, with his longings for the infinite and for happiness, man questions himself about God’s existence. In all this he discerns signs of his spiritual soul. The soul, the seed of eternity we bear in ourselves, irreducible to the merely material, can have its origin only in God” (CCC 33).
Read the rest here.