Having reminded Christians of how great a salvation God has given them in Christ (verses 21-22), and pointing them to their need to persevere in the faith until they are presented before the Lord (verse 22b-23), Paul now steps back and reviews the great sovereign, redemptive plan of God that is revealed from heaven in the gospel of Jesus Christ.

What exactly that plan is, Paul says, God has made very plain. Verse 26 reads, “The mystery hidden for ages and generations but now revealed to his saints.” By mystery, Paul means something that would have remained unknown if God had not revealed it. The sum of this revelation is, “Christ in you, the hope of glory,” and the salvation would be offered to Gentiles as well as Jews (verse 27).

Of course, the gospel of Christ was in all the Old Testament. The Old Testament believers didn’t know the extent of just how great a salvation God promised, but they knew the substance of it. They knew their sinfulness, and they knew dependence upon God’s mercy alone. They looked ahead to the promised Savior, the Messiah, God revealed to them. They were saved by Christ alone.

Paul is teaching us the darkness of this world, meaning the darkness in men’s hearts with respect to God’s nature and the depravity of our own hearts. The world was in need of great salvation, as the misery and death in the world clearly showed, but men walked in darkness. 

So, there was light in the Old Testament for Israel, but when Christ (the eternal Son of God) is born, dies for sinners on the cross, is raised from the dead, and ascends to the right hand of God, and is promised to return in judgment one day; it is then the bright light of God’s redemptive plan shines from heaven. The Light of God shines in his revelation of Jesus Christ.

We are to understand this is a great salvation and a great mercy that has come to us. For Paul, it is remarkable grace that Gentiles are included in the salvation.” Gentiles” mean the nations of men. Anyone with a cursory knowledge of history knows the nations of men have been violent and depraved. There is none among us whose ancestors didn’t walk under the power of the devil before the gospel came to men.

Christ was sent and worked out our salvation that we might have peace, joy, and glory forever. John Bunyan wrote: “He was set forth sweating blood in agony and wrestling with the thoughts of death which he has suffered for our sins. He was nailed to the cross with his arms open wide to show the freeness of his merit would be bestowed on us if we come.”

Paul emphasizes the absolute necessity of coming to Christ genuinely and resting in him alone for salvation: “Him we proclaim, warning everyone and teaching everyone with all wisdom, that we may present everyone mature in Christ (verse 28).” Warnings and teaching the gospel go together. There is much at stake. Matters of life and death are held out to us. So we must listen carefully.

How can there not be warning from those who proclaim the gospel of Christ? In Acts 20, Paul says he warned the church in Ephesus for three years with tears. Warnings from God abound in the Scriptures. God spells it out, makes it very clear. He responds in anger to men’s sin. God is good; he cannot but be disposed in anger toward sin. God reveals his holy anger that we might run to Christ.

Our culture does not believe in God’s anger. It is a righteous anger. The Son of God came into the world to save sinners. There was a great need only he could meet. It is a measure of the infinite love of Christ that he gave himself for us while we were yet enemies of God; that the Father would make him who knew no sin, to be sin for us, so that we might become the righteousness of God in Him.

It is Christ we must have, and Christ we must not resist. When sinners reject the truth of Christ they are striving against Christ as if he was present.  Nevertheless, the gospel represents the infinite willingness of God to be at peace with men.

For you who believe, Paul says the goal is to present you “mature in Christ.” This means sincere, humble, thankful, ready; people who boast in their hearts of Christ and the cross. They love him. They know what he did, and why he did it. They hear the word of God and want to hear it again and again.