The doctrine of illumination does not mean that believers can unlock every theological secret (Deut. 29:29), or that we do not need godly teachers (Eph. 4:11–12). It also does not preclude us from disciplining ourselves for the purpose of godliness (1 Tim. 4:8) or from doing the hard work of careful Bible study (2 Tim. 2:15). Yet we can approach our study of God’s Word with joy and eagerness—knowing that as we investigate the Scriptures with prayerfulness and diligence, the Holy Spirit will illuminate our hearts to comprehend, embrace, and apply the truths we are studying.
John MacArthur