Gill on Private Interpretation

"Of the Holy Scriptures"

"A sure, certain, and infallible rule to go by, with respect to things both to be believed and done: a rule they are (Gal. 6:16). And since they are of divine authority, and are perfect and plain, they are a sure rule, and to be depended on; "The testimony of the Lord is sure", (Ps. 19:7) and a "more sure word of prophecy" than all others whatever, (2 Pet. 1:19) these are the witness of God, and therefore greater than man’s; and to be believed before any human testimony, (1 John 5:9) yea, must be reckoned infallible, since they are the Scriptures of truth, and not only contain what is truth, and nothing but truth in them: but have a true, even a divine testimony bore unto them, and come from the God of truth, who cannot lie (Dan. 10:21; Tit 1:2). They are the judge of all religious controversies, to which all are to be brought, and by them determined; according to these, spiritual men, who have their senses exercised, to discern between good and evil, try and judge all things. The Scripture is the best interpreter of Scripture, or the Spirit of God therein; nor are the church or its pastors, nor councils and popes, the infallible interpreters thereof; there is a private interpretation of Scripture, which every Christian may make, according to his ability and light; and there is a public one, by the preacher of the word but both are subject to, and to be determined by the Scripture itself, which is the only certain and infallible rule of faith and practice."

("A Body of Doctrinal Divinity" - Book 1—Chapter 2)

See here