44 Man is by nature and vocation a religious being. Coming from God, going toward God, man lives a fully human life only if he freely lives by his bond with God.
We all have a natural religiosity, but this needs to be polished by God's revelation through His Church.
A natural religiosity can be found in ancient civilizations which worshiped gods, also the native populations in the Americas such as the Aztecs.
45 Man is made to live in communion with God in whom he finds happiness: When I am completely united to you, there will be no more sorrow or trials; entirely full of you, my life will be complete (St. Augustine, Conf. 10, 28, 39: PL 32, 795}.
A man can go crazy looking around for happiness and never able to find it without God. However a man is happy anywhere he goes by having God in his life, being one with God (John 17:21), even in the midst of tribulations.
46 When he listens to the message of creation and to the voice of conscience, man can arrive at certainty about the existence of God, the cause and the end of everything.
Man is able to attain salvation by loving God (even implicitly by loving neighbor) with a sincere conscience, looking for truth thus attaining a mystical but non-formal baptism of desire or blood. It is quite different, though, for a man who avoids following the truth, in this case he becomes guilty of not looking the truth, preferring darkness instead of light. The easiest, most helpful and most rewarding path to Heaven is by being a faithful Catholic.
47 The Church teaches that the one true God, our Creator and Lord, can be known with certainty from his works, by the natural light of human reason (cf. Vatican Council I, can. 2 # 1: DS 3026),
We can reach at the reasonably conclusion of the existence of God by witnessing His "prints", creation. Nothing can do nothing, but "Something" can do something.
48 We really can name God, starting from the manifold perfections of his creatures, which are likenesses of the infinitely perfect God, even if our limited language cannot exhaust the mystery.
We can reasonably understand God to a limited extent, but never completely, not even in Heaven. God is God, we are limited creatures including the greatest of Angels and God's most marvelous creation after the human nature of Christ, the Blessed Virgin Mary.
49 Without the Creator, the creature vanishes (GS 36). This is the reason why believers know that the love of Christ urges them to bring the light of the living God to those who do not know him or who reject him.
It is our obligation and duty to spread the Good News to this sinful world that there is a better way of living by being immersed in His love, and of having hope in eternal life by being witnesses of our resurrected Lord acting in our lives.
John 3:27; John 15:5; Matthew 19:26