The most notable person after Jesus was a man name Paul. His mission began as a person who despised the followers of this new found "religion". He taunted, and killed people who believed. Until the day his life changed and he was literally brought to his knees. There is much more to that story, see Acts 9. Once converted Saul became Paul and was missioned to spread the gospel (the good news) amongst nations. Here is one of his best letters/speeches to the people of Corinth.
I Corinthians 13:1 If I speak in the tongues of men and of angels, but have not love, I am a noisy gong or a clanging cymbal. And if I have prophetic powers, and understand all mysteries and all knowledge, and if I have all faith, so as to remove mountains, but have not love, I am nothing. If I give away all I have, and if I deliver up my body to be burned, but have not love, I gain nothing.
Love is patient and kind; love does not envy or boast; it is not arrogant 5 or rude. It does not insist on its own way; it is not irritable or resentful; it does not rejoice at wrongdoing, but rejoices with the truth. Love bears all things, believes all things, hopes all things, endures all things.
Love never ends. As for prophecies, they will pass away; as for tongues, they will cease; as for knowledge, it will pass away. For we know in part and we prophesy in part, but when the perfect comes, the partial will pass away. When I was a child, I spoke like a child, I thought like a child, I reasoned like a child. When I became a man, I gave up childish ways. For now we see in a mirror dimly, but then face to face. Now I know in part; then I shall know fully, even as I have been fully known.
So now faith, hope, and love abide, these three; but the greatest of these is love.