Concise Bible Dictionary:

Throughout the scriptures there is that which God designates as “the truth.” It is divine, and above the opinions of men, however wise and pious they may be. In the Old Testament the admonition is given, “Buy the truth and sell it not” (Prov. 23:23). “The truth” must refer to God, who is true, but is not called “the truth:” hence it comprises all that may be known of God, whether declared by creation or made known by revelation. Truth is not simply that which is held as dogma, but must be received in the soul. Paul asked the Galatians who had hindered them that they should not obey “the truth?” (Gal. 5:7). Judgment is coming upon Christendom “because they received not the love of the truth that they might be saved” (2 Thess. 2:10). Truth is the real way of liberty: “the truth shall make you free” (John 8:32,36). Truth cannot be separated from the Lord Jesus, who is “the way, the truth, and the life.” This is objectively; subjectively the Spirit is the truth as having come from the glorified Christ. In the three Epistles of John “the truth” is constantly referred to, and a Christian woman is warned not to receive any one into her house, nor wish him God-speed unless he holds the doctrines taught by the apostles—in other words, “the truth.”