Revelation: Gods’ manifestation of Himself to particular persons at definite times and places, enabling those persons to enter into a redemptive relationship with Him.
Inspiration: God superintended the human authors of the Bible so that they composed and recorded without error His message to mankind in the words of their original writings.
Illumination: the work of God’s Spirit as He aids us in appropriating the truth of the Scriptures which God has revealed.
Inscripturation: when what is communicated in revelation is committed to writing.
Revelation is when God makes truth known to man, while inspiration is the communicating of that truth. Inscripturation is the writing down of the truth that has been revealed, while illumination is God’s work in the believer when He helps us acquire, grasp, and understand the truth that was inscripturated.
Without revelation of truth, there can be no communicating of truth and so inspiration can not exist without revelation. Without inspiration of revelation, there can be no composition without error of God’s revealed truth, and so no inscripturation. Without Scriptures to read, there can be no appropriating of the truth God revealed in them, and so no illumination. Without any one of these, man can not truly know what God has revealed in the past, so how would we know what He wants for us or from us? Without God, these are all meaningless terms. Only with God are these possible. Man is prone to mistakes. We tend to think about something and decide that if it makes sense, given the information we know then it must be true. We fool ourselves that our knowledge is complete. Only God has all knowledge. Only God knows what is actually true. Only He can reveal it to man in such a way so as to ensure we do not confuse it with our own musings. Once God has chosen to reveal it, only God can communicate it without error, be it verbally or in writing. And once communicated, only God can ensure the truth is understood without error.