Though this could be a very long study I am going to just cover some basics and then encourage you to dig further.
Hebrews 1:1-2 says: "God, after He spoke long ago to the fathers in the prophets in many portions and in many ways, in these last days has spoken to us in His Son, whom He appointed heir of all things, through whom also He made the world."
God did speak at times through prophets and then He spoke through Jesus Christ who came to earth to live and die for us.
We know that Moses was the writer of the first 5 books of the Bible. In Exodus 24:4 it says "Moses wrote down all the words of the Lord." Exodus 33:11 says "Then the Lord used to speak to Moses face to face, just as a man speaks to his friend."
How about the rest of the writers of the Old Testament? Did God speak to them face to face as well? No. Deuteronomy 34:10 says "Since that time no prophet has risen in Israel like Moses, whom the Lord knew face to face." So how did they receive God's word to write it down? It seems that it was revealed to them through visions (Check out Isaiah 1:1, Ezekiel 1:1, Jonah 1:1 and more). 2 Peter 1:21 says: "For no prophecy was ever made by an act of human will, but men moved by the Holy Spirit spoke from God."
What about the New Testament writers? Hebrews 1:2 (quoted above) says that God spoke to us through His Son. Hebrews 9:15 says: "For this reason He is the mediator of a new covenant, so that, since a death has taken place for the redemption of the transgressions that were committed under the first covenant, those who have been called may receive the promise of the eternal inheritance."
But did Jesus write every word in the New Testament? No. Men did - Apostles and followers of Jesus Christ.
John 17:7 and 8 says: "Now they have come to know that everything You have given Me is from You; for the words which You gave Me I have given to them; and they received them and truly understood that I came forth from You, and they believe that you sent Me." So Jesus was busily teaching them while He was here. Then just before He left earth He told them: All authority has been given to Me in heaven and on earth. "Go therefore and make disciples of all the nations, baptizing them in the name of the Father and the Son and the Holy Spirit, teaching them to observe all that I commanded you; and lo, I am with you always, even to the end of the age." Matthew 28:18-20 These were men however and men can forget but Jesus promised them: "These things I have spoken to you while abiding with you. But the Helper, the Holy Spirit, whom the Father will send in My name, He will teach you all things, and bring to your remembrance all that I said to you." John 14: 25 & 26.
The Holy Spirit played a huge role in helping the writers of the New Testament. Read John 16:12 & 13: " I have many more things to say to you, but you cannot bear them now. But when He, the Spirit of truth, comes, He will guide you into all the truth; for He will not speak on His own initiative, but whatever He hears, He will speak; and He will disclose to you what is to come." Ephesians 3:3-5 says: " That by revelation there was made known to me the mystery, as I wrote before in brief. By referring to this, when you read you can understand my insight into the mystery of Christ, which in other generations was not made know to the sons of men, as it has now been revealed to His holy apostles and prophets in the Spirit." On day of Pentecost it says: "And they were all filled with the Holy Spirit and began to speak with other tongues, as the Spirit was giving them utterance." Acts 2:4
The apostle Paul, who wrote many of the New Testament books, had a little different situation as he had not physically walked with Christ. Galatians 1:11 & 12 speaks of that: "For I would have you know, brethren, that the gospel which was preached by me is not according to man. For I neither received it from man, nor was I taught it, but I received it through a revelation of Jesus Christ."
The words in the Bible are life changing. The have the message that will give us hope and purpose throughout eternity. I believe they are from God and that we need to treat them with respect and study them so we can better know how to live and be prepared to die.
2 Peter 3:16 says: "as also in all his letters, speaking in them of these things, in which are some things hard to understand, which the untaught and unstable distort as they do also the rest of the Scriptures, to their own destruction." Let's be really careful not to distort or take lightly God's word!
If you are trying to read the Bible through in 2017 or just want to keep track of your reading this site has a lot of different printable charts that you can use. I personally like the one where it just has all the books and chapters listed and I can mark them off and read through it in my own way.
This blog post was inspired by a book that I am going through: "52 simple stimulating studies" by Donald Hunt (one of my Bible College professors).