Jesus is not just King - He is Eternal King. From everlasting to everlasting. Forever has been and forever will be. When you try to figure this out, we realize the limits of our brain power. God existed outside of time, before he created time, and he will exist when time shall be no more. We cannot fathom that because we cannot comprehend a time without time. And we cannot comprehend the idea of not getting old. Everything in our world changes. Things rise and fall, are born, grow, and die. Water flows - the hydrological cycle shows that the clouds bring the rain, which nourishes the field and flows into streams, rivers, and oceans, only to evaporate into the air to repeat. Yet God never changes. And yet, for all of eternity, we can be learning about him, because knowing God is an inexhaustible endeavour! We can try, but I don't think we can understand that.