God Is Supreme, Faithful, and True, Therefore His Word is Supreme, Faithful and True

God is supreme- He is Creator and all powerful. This is made known by His handiwork of creation & all know it:

Psa 19:1 To the choirmaster. A Psalm of David. The heavens declare the glory of God, and the sky above proclaims his handiwork. 
Psa 19:2 Day to day pours out speech, and night to night reveals knowledge.
Psa 19:3 There is no speech, nor are there words, whose voice is not heard. 
Psa 19:4 Their voice goes out through all the earth, and their words to the end of the world. In them he has set a tent for the sun,

Rom 1:19 For what can be known about God is plain to them, because God has shown it to them. 
Rom 1:20 For his invisible attributes, namely, his eternal power and divine nature, have been clearly perceived, ever since the creation of the world, in the things that have been made. So they are without excuse.

Because God is supreme and all powerful, so is His Word:

Psa 19:6 Its rising is from the end of the heavens, and its circuit to the end of them, and there is nothing hidden from its heat.
Psa 19:7 The law of the LORD is perfect, reviving the soul; the testimony of the LORD is sure, making wise the simple; 
Psa 19:8 the precepts of the LORD are right, rejoicing the heart; the commandment of the LORD is pure, enlightening the eyes;

His Word is living b/c He is living; His Word is faithful and true because it's Author is faithful and true:

Rev 1:8 "I am the Alpha and the Omega," says the Lord God, "who is and who was and who is to come, the Almighty."

Rev 1:16 In his right hand he held seven stars, from his mouth came a sharp two-edged sword, and his face was like the sun shining in full strength.

Rev 1:18 and the living one. I died, and behold I am alive forevermore, and I have the keys of Death and Hades.

Heb 4:12 For the word of God is living and active, sharper than any two-edged sword, piercing to the division of soul and of spirit, of joints and of marrow, and discerning the thoughts and intentions of the heart. 
Heb 4:13 And no creature is hidden from his sight, but all are naked and exposed to the eyes of him to whom we must give account.

Rev 3:7 "And to the angel of the church in Philadelphia write: 'The words of the holy one, the true one, who has the key of David, who opens and no one will shut, who shuts and no one opens.

Rev 3:14 "And to the angel of the church in Laodicea write: 'The words of the Amen, the faithful and true witness, the beginning of God's creation.

Rev 19:9 And the angel said to me, "Write this: Blessed are those who are invited to the marriage supper of the Lamb." And he said to me, "These are the true words of God."

Rev 19:11 Then I saw heaven opened, and behold, a white horse! The one sitting on it is called Faithful and True, and in righteousness he judges and makes war.

Rev 19:13 He is clothed in a robe dipped in blood, and the name by which he is called is The Word of God.

Rev 19:15 From his mouth comes a sharp sword with which to strike down the nations, and he will rule them with a rod of iron. He will tread the winepress of the fury of the wrath of God the Almighty.
Rev 19:16 On his robe and on his thigh he has a name written, King of kings and Lord of lords.

Rev 21:5 And he who was seated on the throne said, "Behold, I am making all things new." Also he said, "Write this down, for these words are trustworthy and true."

Rev 22:6 And he said to me, "These words are trustworthy and true. And the Lord, the God of the spirits of the prophets, has sent his angel to show his servants what must soon take place."

Psa 19:7  The law of the LORD is perfect, reviving the soul; the testimony of the LORD is sure, making wise the simple; 

"Sure": certain, reliable, solid, firm, trustworthy. NOT false, a myth, or speculation.

The testimony of God in Creation and in the Word (all it's teaching and instruction) is certain and is knowable. It gives wisdom to the simple. This begins with Gen. 1:1. The foremost description of God is that He is Creator and therefore is to be feared and obeyed. Just as in Ps 19:1-6 begins with God's glory as Creator, so does Gen. 1:1. Explicit and sure--CERTAIN & TRUE--testimony of the Divine Creator.

To deny the SURE testimony of God as Divine Creator who personally created all things in six literal days (Ps 8 & 33), is to remain simple (foolish) since Truth is only revealed in Scripture, particularly about God's character and power and eternality, starting in Gen. 1:1.

The testimony of God as the omnipotent Creator Is:

sure
right
pure

and it enlightens the eyes.

To deny the sure testimony God gives about Himself is to deny therefore those truths and His character. It means one remains blind and in darkness:

Eph 4:17  Now this I say and testify in the Lord, that you must no longer walk as the Gentiles do, in the futility of their minds. 
Eph 4:18  They are darkened in their understanding, alienated from the life of God because of the ignorance that is in them, due to their hardness of heart.
Eph 4:19  They have become callous and have given themselves up to sensuality, greedy to practice every kind of impurity.
Eph 4:20  But that is not the way you learned Christ!—
Eph 4:21  assuming that you have heard about him and were taught in him, as the truth is in Jesus,

Truth is knowable. We are not groaping around in the dark if we are truly in Christ. God has revealed Himself and moreover, enlightened the eyes of those He regenerates. But all people KNOW God exists and is Creator as Rom. 1 explicitly states.