Creation is God's Expression

The heavens declare the glory of God;
the skies proclaim the work of his hands.
Day after day they pour forth speech;
night after night they display knowledge.
There is no speech or language
where their voice is not heard.
Their voice goes out into all the earth,
their words to the ends of the world.(Psalm 19:1-4, NIV)

By the word of the LORD were the heavens made,
their starry host by the breath of his mouth.(Psalm 33:6, NIV)

Why did God create our world? God's purpose is beyond our ability to understand. Yet, God expresses Himself in creation. Psalms 33:9 explains Psalms 33:6 (above) that God created by speaking, "let there be..."
(Genesis 1:3,6,9,11,14-15,20,24,26; Matthew 5:16; 2 Corinthians 4:6)
Another way of stating to express God is to glorify God.
(Isaiah 43:21; 44:23; 49:3; 60:21; Ephesians 1:11-12)
As God's creatures, our purpose is to express who God is. Created in the image of God, our purpose is to reflect God's glory
(Matthew 5:14-16,48; 2 Corinthians 3:18-4:6; Ephesians 4:22-24, 5:1-2)
just as the moon reflects the sun's light. Thus, the church's primary responsibility is to worship God
(1 Chronicles 29:20; Psalm 97:7-9; 100:1-5; Romans 12:1-2; Colossians 3:12-24; Hebrews 13:15)
. When Christians consider their purpose to express God, this gives new meaning to our roles as children
(John 5:19; Ephesians 6:1-3; Colossians 3:20)
, husbands
(Ephesians 5:25-33; Colossians 3:19)
, wives
(1 Corinthians 11:3; Ephesians 5:22-24; Colossians 3:18)
, parents
(Deuteronomy 6:7-9; Psalm 103:13; Proverbs 3:11-12; Matthew 7:9-11; John 5:20; Ephesians 6:4; Colossians 3:21; Hebrews 12:5-11)
, employers
(Ephesians 6:9; Colossians 4:1)
, and employees
(Ephesians 6:5-8; Colossians 3:22-23)
. Rather than God finding ways to express His relationship to us, God created our relationships as an integral part of who He is
(Isaiah 48:9-11)
. In other words, the standard for these relationships is God's own character
(Leviticus 11:44; 19:2; Matthew 5:48)
God created more than the material world. He created who we are on the inside as well. Because God values the inner person more than outward appearance
(1 Samuel 16:7; Psalm 147:10-11; Luke 16:15; 1 Peter 3:4)
, He desires foremost to express Himself in our hearts
(Deuteronomy 6:8; Jeremiah 31:33-34)
. God brought His revelation to a climax with His coming as a human being, Jesus Christ
(John 1:14; Colossians 2:9; Hebrews 1:1-4)
, to save us from our sins
(John 1:11-13; 3:16-17)
. This truth as recorded in the Bible, the circumstances of life
(Romans 8:28-39)
, and the beauty of nature
(Romans 1:20)
are to make God known in our lives
(Philippians 3:7-11)