What Do You Need to Do in Order to Eternal Life?

John does not use the word kingdom but two times he uses the word life some sixty years after the other synoptic gospels were written. Matthew Mark and Luke all talk about the kingdom Matthew talks about the kingdom of heaven Mark and Luke talk about the kingship of God. John begins to say even the kingdom has become something that is a thing in verse 21. The man wanted to make the conversation about eternal life which in their culture as well as ours would have meant the afterlife what do I need to do in order to inherit life eternal?