or putting it another way...if we are citizens of heaven, and our ultimate goal and destination as children of God is to be in heaven, then in this lifetime it behooves us to learn all about God and Jesus who rule over that country.
We do this by accepting Jesus as our saviour and by believing and studying the religion of Christianity, not by believing and studying other religions.
we also realize that there are other people who do not yet know Christ, or have never heard about Him. Nontheless, our loving God thru Jesus has created and put all the things on earth around them as a witness to Himself, so that those people also have the same opportunity as we have to learn about Jesus and about God while they live here on earth.
He sends Christian believers their way who tell them of Himself and of His Son, Jesus, and He gives them opportunities to learn who He is--that Jesus His Son is the only way, that Jesus alone is the eternal truth, and that God's gift to them is eternal life if they place their faith and trust in Him and in His Son, Jesus. it is a life-changing experience with eternal benefits that can never be taken away from them. Living life with Jesus in your heart really is a new life, because we are changed in our hearts.
Now instead of living our life alone, we live our lives with Jesus beside us. He helps us every day and He teaches us how to live in our new lives. He gives us joy instead of sorrow, life instead of bondage, and hope instead of dispair.
We watch Him and we study His life so we can learn how He did things while here, and how He handled problems or difficult situations. And we learn how to do those things ourselves with His constant help and loving guidance. And as we learn, we become more and more like Him, which pleases God. And as we do so, we begin to understand how He thought. we begin to see our world thru His eyes, to see people as He sees them, and to know how much He loves.
the Bible calls this faith and this Christian way of living 'the pearl of great price'; a treasure worth finding for which a man would sell all he had just to own it. And yet the cost of this great gift from God has already been paid for, thru the sacrifice of Jesus, the Son of God, who died once to attone for all our sins that we would ever commit in this life, and who then rose victorious over death and the grave to live eternally. No one else, before or since that time thru today had ever done that before in the history of the whole world.
This salvation is a gift offered to us by God--salvation from the penalty of our sins, and living an eternal life with Him, and his Son, Jesus, and the Comforter known as the Holy Spirit.
so this is why we don't study other religions. because having found that great pearl, we could never be satisfied with anything or anyone else.