By Preaching

Titus 1:1-3

"Paul, a bond-servant of God and an apostle of Jesus Christ, for the faith of those chosen of God and the knowledge of the truth which is according to godliness, in the hope of eternal life, which God, who cannot lie, promised long ages ago, but at the proper time manifested, even His word, in the proclamation with which I was entrusted according to the commandment of God our Savior"

How has the knowledge of the truth been manifested at the proper time? By the kerugmati. Or in English, "preaching" or as in the NASB "proclamation." Paul saw God's revelation as primarily being revealed through his preaching, not miracles, healings, wonders, etc. He was entrusted with the message of the Gospel. He saw his preaching ministry as a direct commission from the Lord. He was responsible for making known the mystery to the world (Ephesians 3:8-12). Do you want to know the mysteries of God, the history of redemption, the glories of heaven? Listen to preaching. It is the divinely ordained means through which men might come to a knowledge of the turth. It is no wonder why Paul would charge Timothy so solemnly to "Preach the Word" (2 Timothy 4:2).