"The Heavens declare the glory of God, and their expanse shows his handy-work (Psalm 19:1)."
"...because that which is known about God is evident within them; for God made it evident to them . . . being understood through what has been made, so that they are without excuse (Rom 1:20-21)."
These scriptures point out the evidence for a creator. Why does something exist instead of nothing? The axiom that every effect has a cause leads you back to an original cause, which we believe is the God of the Bible.
But it is not merely the existence of matter that declares the glory of God. The intricate, orderly, beautiful design of our world points to evidence of a designer. It would be absurd to assume that this computer I am sitting in front of came into existence randomly, or by a "big bang." That would be like saying this computer came together in perfect working order as the result of truck getting into a bad wreck that was carrying electronic parts.
To give you an idea of the delicate, intricacies of order in our world, consider these two examples from our own human bodies.
1. The circulatory system of the human body is longer than the U.S. railroad system (60,000 to 100,000 miles). Yet the heart pumps the exact amount of blood needed which is five quarts a minute. If there is a breach, the blood clots to stop the leak. Pretty ingenious.
2. A single human DNA is a micro cell with all the "blueprint" for a particular person encoded on it. It contains information on every single part of your body, including hair color, facial features, etc. All 13 billion cells in your body has the same DNA, and your DNA is like no one else's which is what makes you unique from others. If the sequence in your DNA were to be written down, it would fill every page of every volume of 40 sets of Encyclopedia Britannica!
There are many other examples, such as the amount of oxygen in our atmosphere, the rotation of the earth, the distance of the earth from the sun, etc., but you get the idea. There is evidence of an intelligent designer in our universe. The odds of the world happening by chance are preposterous. Take this mathmatical lesson in odds: In a jar are 99 black marbles and 1 white one. The odds of getting the white marble out randomly are: 1st try - 1 out of 100; 2nd try - 1 out of 10,000; 3rd try - 1 out of 1,000,000!
When you consider the sheer number of variables involved in making our world work, it becomes obvious that our world did not come into being by chance. To say that the world happened by chance is as ridiculous as saying that Webster's Unabridged Dictionary is a result of an explosion at a print factory! As the passage above has said, God has made himself evident through his creation.