Heaven is even now mirrored in created things. All God's creatures invite us to forget our vain cares and enter into out own hearts, which God Himself has made to be His paradise and our own. If we have God dwelling within us, making our souls His paradise, then the world around us can also become for us what it was meant to be for Adam--his paradise. But if we seek paradise outside ourselves, we cannot have paradise in our hearts. If we have no peace within ourselves, we have no peace with what is all around us. Only the man who is free from attachment finds that creatures have become his friends. As long as he is attached to them, they speak to him only of his own desires. Or they remind him of his sins. When he is selfish, they serve his selfishness. When he is pure, they speak to him of God.
If we are not grateful to God, we cannot taste the joy of finding Him in His creation. To be ungrateful is to admit that we do not know Him, and that we love his creatures not for His sake but for our own. Unless we are grateful for our own existence, we do not know who we are, and we have not yet discovered what it really means to be and to live. No matter how high an estimate we may have of our own goodness, that estimate is too low unless we realize that all we have comes to us from God.
The only value of our life is that it is a gift of God.
Gratitude shows reverence to God in the way it makes use of His gifts.