You can guess, or you can speculate, or if you believe that God exists, and that He is a loving God, you can simply take Him at His word:
2 Peter 1
20 Knowing this first, that no prophecy of the scripture is of any private interpretation.
21 For the prophecy came not in old time by the will of man: but holy men of God spake as they were moved by the Holy Ghost.
11 But I certify you, brethren, that the gospel which was preached of me is not after man.
12 For I neither received it of man, neither was I taught it, but by the revelation of Jesus Christ.
2 Timothy 3
16 All scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness:
17 That the man of God may be perfect, throughly furnished unto all good works.
21 Oh that men would praise the LORD for his goodness, and for his wonderful works to the children of men!