From the Word 

“No one has ever seen God.  The only begotten God, who is in the bosom of the Father, He has made Him known.”  John 1:18 

    In the beginning there was God.  He did not have to make Himself known to His perfect creation, because they walked with Him in perfect harmony.  But since the fall into sin, people have been wrong about God, or not known Him at all.  The problem has never been God, since He has not changed.  The problem is sinful people.
    Since God has not changed, some would assume that explaining Him has not changed either.  That is not the case.  In various generations there was a general agreement that there is a god, so teaching people about Him was simply building on what they already knew.  Most people in various eras of history saw the wonder of creation and assumed there was a god who made it all.  Christians in those generations simply had to introduce them to the one true God, of whom they had natural knowledge.  That introduction was God’s self-revelation in Jesus.
    God is no different in our generation, but the challenge of presenting Him to those around us is.  People in our generation have made a concerted effort to deny any knowledge of God, including the natural assumption that there is one.  Nature has become an end to itself, becoming the explanation for all things, even though that explanation defies the complexity of what we see.  Natural knowledge of God is shot down by so-called scientific knowledge.  These voices who scream for us Christians to be tolerant of their viewpoints are unwilling to listen to dissent, let alone tolerate it.
    Even though God has not changed, we are called to change how we witness of Him.  We are no longer explaining one of whom they have some prior knowledge.  We are now introducing a new idea.  Thankfully, the key to explaining God without prior knowledge leads us to the same source; Jesus. 
    God cannot be truly known apart from His self-revelation.  That revelation comes in His Word, centered on God incarnate, who was promised, came, and dwells with us.  This is Jesus.  We cannot understand God apart from Jesus, He is simply too mysterious.  What we know about God, we know because of Jesus.  So our task is to introduce the idea, and reality, of God in Jesus.  We will tell them, and teach them, about Jesus; the unchanging God in a changing world.