Internal evidence:

a) Over 3800 references in Old Testament declare that God is speaking.

Isaiah 55:8 For my thoughts are not your thoughts, neither are your ways my ways, saith the LORD.

Genesis 12:1 Now the LORD had said unto Abram, Get thee out of thy country, and from thy kindred, and from thy father’s house, unto a land that I will shew thee:

Exodus 7:17 Thus saith the LORD, In this thou shalt know that I am the LORD: behold, I will smite with the rod that is in mine hand upon the waters which are in the river, and they shall be turned to blood.

Numbers 4:1 And the LORD spake unto Moses and unto Aaron, saying…

Jeremiah 11:1 The word that came to Jeremiah from the LORD, saying,..

b) Jesus Christ – The Word of God

Hebrews 1:1 God, who at various times and in various ways spoke in time past to the fathers by the prophets, 2 has in these last days spoken to us by His Son, whom He has appointed heir of all things, through whom also He made the worlds;

John 1:1 In the beginning was the Word, and the Word was with God, and the Word was God.

John 1:14 And the Word became flesh and dwelt among us, and we beheld His glory, the glory as of the only begotten of the Father, full of grace and truth.

Revelation 19:13 And he was clothed with a vesture dipped in blood: and his name is called The Word of God.

c) The words written by the apostles

1Corinthians 14:37 If any man think himself to be a prophet, or spiritual, let him acknowledge that the things that I write unto you are the commandments of the Lord.

2Timothy 3:16 All scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness:

External evidence:

a) Historical and archeological evidence:

Bible names historical cities: Abraham was from Ur of Chaldees, an ancient Mesopotamian city. So are the cities, Jericho, Canaan, Egypt.

Bible also names historical figures such as Potiphar, Rameses, and Nebuchadnezzar.
Bible’s version of Israelite history during the reign of king David and Solomon is believed to be true even by the secular scholars because it is validated by independent account of Egyptian and Assyrian inscriptions.

Jewish historian, Josephus, in his book makes references to Jesus Christ. Roman historian Tacitus refers to Christ and the execution order given by Pontius Pilate.

b) The fulfilled prophesies:

There are about 2500 prophecies that appear in the Bible. Out of which about 2000 of them are already fulfilled to the letter.

The destruction of impregnable Babylon by Cyrus king of Medes was prophesied by two prophets, Isaiah (13:17-22) and Jeremiah (51) about 150 years before Cyrus was born.

Prophecy of the rise and fall of 4 great kingdoms in Daniel 2

Jesus Christ’s birth, ministry, death and resurrection were prophesized 400 years before his birth and were fulfilled accurately.

c) Consistency and preservation of the scriptures:

The 66 books in the Bible were written in 3 languages (Hebrew, Aramic, Koine Greek) over a period of 1600 years by 40 authors from various forms of lives: shepherds, kings, statesmen, scholars, priests, tax collectors, poets, historians, fishermen, doctors and lawyers. Yet the Bible is consistent with the theology and theme: one problem – sin, and one solution – Jesus Christ.

d) Scientific coherence:

1. Earth is a sphere hanging in empty space
   Isa 40:22 It is he that sitteth above the circle of the earth
   Job 26:7 He stretches out the north over the void and hangs the earth on nothing.
2. Air has weight
   Job 28:25 When he made a weight for the wind, measuring out the waters;
3. Blood is a source of life in the physical man
   Leviticus 17:11 For the life of the flesh is in its blood
4. Hydrological Cycle (Rainfall)
   Job 36:27 For He draws up drops of water, which distill as rain from the mist, 28 Which the clouds drop down And pour abundantly on man
   Psalm 135:7 He causes the vapors to ascend from the ends of the earth; He makes lightning for the rain; He brings the wind out of His treasuries.
5. Springs on the ocean floor and Paths of sea
   Job 38:16 Have you gone to the springs of the sea? Or have you walked in search of the depths?
   Psalm 8:8 The fowl of the air, and the fish of the sea, and whatsoever passeth through the paths of the seas.
6. Accurate record of a mature creation
   Genesis 1:11 Then God said, “Let the earth bring forth grass, the herb that yields seed, and the fruit tree that yields fruit according to its kind, whose seed is in itself, on the earth”; and it was so. 12 And the earth brought forth grass, the herb that yields seed according to its kind, and the tree that yields fruit, whose seed is in itself according to its kind. And God saw that it was good.
7. Composition of man
   1Thessalonians 5:23 And the very God of peace sanctify you wholly; and I pray God your whole spirit and soul and body be preserved blameless unto the coming of our Lord Jesus Christ.