2 Peter 1:21 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.
The most important subject in the Bible to become informed about and convinced of is the subject of what the Bible says about itself. If you miss understanding this, you really miss much of the value that the Bible possesses as a source of encouragement to your life. The Bible is no ordinary book. The Bible was inspired by God Himself. Although the writers of the Bible used their own words and vocabulary, and often write in a manner that reflects their individual personality and life experience, the message they proclaim and the words chosen to convey that message are not their own, but those chosen by the Holy Spirit. The Holy Spirit is a Divine Person, the third member of the Trinity. Though you will not find the word “trinity” in the Bible itself, careful study of the Biblical evidence will demonstrate that the Bible teaches there is One God who exists eternally in three distinct persons, each of whom is called God. The Bible calls Jesus God; the Bible calls the Holy Spirit God; and no one who accepts the Bible as the inspired written Word of God has any doubt that the Father is called God. But the point of this text, 2 Peter 1:21, is that the men chosen by God to write the Bible did not write their own opinion, but wrote authoritatively the message God gave them to convey to us.
For those who desire to DIG DEEPER into this subject:
(1) Consult the cross references given in Nelson’s Cross Reference Guide to the Bible on page 1466 for 2 Peter 1:21.
(2) Consult the cross references given in The New Treasury of Scripture Knowledge on page 1485 or in Logos 5 Bible software for 2 Peter 1:21.
(3) Lacking access to those two resources, consult the cross references for this passage as I have developed them as given below:
2 Peter 1:21. the prophecy. Lk *1:70. 2 T +*3:16. 1 P *1:11. in old time. or, at any time. holy. Dt *33:1. Jsh 14:6. 1 K 13:1. *17:18, 24. 2 K 4:7, 9, 22. *6:10, 15. 1 Ch *23:14. 2 Ch 8:14. spake. Nu 16:28. 2 S *23:2. Mi +*3:7. Lk 1:70. 2 T +**3:15-17. 1 P *1:11. Re *19:10. they were. or, being. FS63K, Ge +37:13. by the Holy. Mk 12:36. Ac 1:16. 3:18. 28:25. He 3:7. 9:8. 10:15. Ghost. Gr. pneuma, Mt +1:18.