Answer: To convert others to Christianity
Explanation:
In the book of Matthew 28: 16 - 20, Jesus Christ who had just risen issued to Great Commission to his disciples before he went back to heaven.
The Great Commission was that his disciples go into the world and spread the good news of God and to convert people to the cause which later came to be known as Christianity.
This is the reason why Christianity spread at such a rate in those times and why Evangelism and Missionary work are such cornerstones in Christianity.
