LOL, Christianity Today features female contributor who simply ignores the slave language of the New Testament, saying she's no servant

 Human Beings Are Stewards, Not Slaves to God

I’m not merely an inglorious servant to the divine . . .. 

 

She also ignores The Fall in the Christian origin story, which is her topic, and Eve's role in it.

 

What a shock, right?

None is able to serve two lords, for either he will hate the one and love the other, or he will hold to the one, and despise the other; ye are not able to serve God and Mammon.

 

-- Matthew 6:24

So you too, when you do all the things which were commanded you, say, 'We are unworthy slaves; we have done only that which we ought to have done.'

 

-- Luke 17:10

 

Truly, truly I say to you, a slave is not greater than his master, nor is one who is sent greater than the one who sent him.

 

-- John 13:16

 

No longer do I call you slaves, for the slave does not know what his master is doing; but I have called you friends, because all things that I have heard from My Father I have made known to you.

 

-- John 15:15

 

For am I now seeking the favor of men, or of God? Or am I striving to please men? If I were still trying to please men, I would not be a slave of Christ.

-- Galatians 1:10

Paul, a slave of Christ Jesus, called as an apostle, having been set apart for the gospel of God.

-- Romans 1:1

For the one who was called in the Lord as a slave, is the Lord's freed person; likewise the one who was called as free, is Christ's slave.

-- I Corinthians 7:22

For though I am free from all people, I have made myself a slave to all, so that I may gain more. 

 

-- I Corinthians 9:19

 

. . . just as you learned it from Epaphras, our beloved fellow slave, who is a faithful servant of Christ on our behalf.

 

-- Colossians 1:7

Tychicus, our beloved brother and faithful servant and fellow slave in the Lord, will make known to you all my affairs.

-- Colossians 4:7

Paul, a slave of God and an apostle of Jesus Christ . . ..

-- Titus 1:1

James, a slave of God and of the Lord Jesus Christ, To the twelve tribes who are in the Dispersion: Greetings.

 -- James 1:1

Jude, a slave of Jesus Christ, and brother of James, To those who are the called, beloved in God the Father, and kept for Jesus Christ:

-- Jude 1:1

And a white robe was given to each of them; and it was told to them that they should rest for a little while longer, until the number of their fellow slaves and their brothers who were to be killed even as they had been, would be completed also.

-- Revelation 6:11

And they sang the song of Moses, the slave of God, and the song of the Lamb, saying . . ..

-- Revelation 15:3

And a voice came from the throne, saying, 'Give praise to our God, all you His slaves, you who fear Him, the small and the great.'

-- Revelation 19:5

Then I fell at his feet to worship him. But he said to me, 'Do not do that! I am a fellow slave with you and your brothers who have the witness of Jesus. Worship God! For the witness of Jesus is the spirit of prophecy.'

-- Revelation 19:10

I, John, am the one who was hearing and seeing these things. And when I heard and saw, I fell down to worship at the feet of the angel who showed me these things. But he said to me, 'Do not do that! I am a fellow slave with you and your brothers the prophets and with those who keep the words of this book. Worship God!'

-- Revelation 22:8f.

If Gnostic ideas are "essentially apostate" and "heretical", the question of their necessary and actual origin in Paul, for example, is simply being begged

The Gnostic heresy’s political successors :

First, they are all essentially apostate projects, enterprises that have arisen in the midst of Christian civilization with the aim of supplanting it.  And they could have arisen only within the Christian context, because, second, these projects are all heretical in the broad sense of that term.  That is to say, they are all founded on some idea inherited from Christianity (the dignity of the individual, human equality, a law-governed universe, a final consummation, etc.) but removed from the theological framework that originally gave it meaning, and radically distorted in the process. ... the key marks of the Gnostic mindset – the positing of unseen malign forces, the hermeneutics of suspicion and “dream world” theorizing, Manicheanism and shrill intolerance of all dissenters, even something like an immanentized eschaton (“The Storm”). 

For we wrestle not against flesh and blood, but against principalities, against powers, against the rulers of the darkness of this world, against spiritual wickedness in high places. -- Ephesians 6:12

Howbeit we speak wisdom among them that are perfect: yet not the wisdom of this world, nor of the princes of this world, that come to nought: But we speak the wisdom of God in a mystery, even the hidden wisdom, which God ordained before the world unto our glory: Which none of the princes of this world knew: for had they known it, they would not have crucified the Lord of glory. But as it is written, Eye hath not seen, nor ear heard, neither have entered into the heart of man, the things which God hath prepared for them that love him. But God hath revealed them unto us by his Spirit: for the Spirit searcheth all things, yea, the deep things of God. For what man knoweth the things of a man, save the spirit of man which is in him? even so the things of God knoweth no man, but the Spirit of God. Now we have received, not the spirit of the world, but the spirit which is of God; that we might know the things that are freely given to us of God. Which things also we speak, not in the words which man's wisdom teacheth, but which the Holy Ghost teacheth; comparing spiritual things with spiritual. But the natural man receiveth not the things of the Spirit of God: for they are foolishness unto him: neither can he know them, because they are spiritually discerned. But he that is spiritual judgeth all things, yet he himself is judged of no man. For who hath known the mind of the Lord, that he may instruct him? But we have the mind of Christ. -- I Corinthians 2:6ff. 

Be not ye therefore partakers with them. For ye were sometimes darkness, but now are ye light in the Lord: walk as children of light: ... And have no fellowship with the unfruitful works of darkness, but rather reprove them. ... Wherefore he saith, Awake thou that sleepest, and arise from the dead, and Christ shall give thee light.  -- Ephesians 5:7f.,11,14

Giving thanks unto the Father, which hath made us meet to be partakers of the inheritance of the saints in light: Who hath delivered us from the power of darkness, and hath translated us into the kingdom of his dear Son:  -- Colossians 1:12f.

The harebrained Peter Leithart writes that "we fill up what is lacking in Christ’s suffering" at First Things

Here.

It's a textbook example of ignorant exegesis, in this case of Colossians 1:24.

Who now rejoice in my sufferings for you, and fill up that which is behind of the afflictions of Christ in my flesh for his body's sake, which is the church

Νῦν χαίρω ἐν τοῖς παθήμασιν μου ὑπὲρ ὑμῶν καὶ ἀνταναπληρῶ τὰ ὑστερήματα τῶν θλίψεων τοῦ Χριστοῦ ἐν τῇ σαρκί μου ὑπὲρ τοῦ σώματος αὐτοῦ ὅ ἐστιν ἡ ἐκκλησία

Paul isn't saying there's anything insufficient or lacking in Christ's afflictions. He's saying he himself is lacking in them, which is why he says to begin with that he rejoices in his sufferings.

Those sufferings fill up what he asserts to be a deficit of them in his experience, "in my flesh" (ἐν τῇ σαρκί μου), which might seem surprising given his statements elsewhere about their ubiquity in his missionary activity. So Paul is clearly speaking a little hyperbolically about himself here. Or perhaps ironically. In comparison with most every one of his contemporaries, he has already suffered much. The point Paul wishes to make is that his service to the church as Apostle to the Gentiles is validated when he experiences suffering and affliction, and so he welcomes those things. The more he suffers for the sake of the gospel, the more the church should know the validity of his calling. "When I am weak, then am I strong", etc.   

This is an entirely autobiographical statement by Paul as an apostle, an example of the defense of himself he is wont to make against his opponents, rather than a recommendation for or illustration of the normal Christian life (compare his counsel elsewhere to ordinary folk to live peaceably with all men, live quietly, work with your hands, etc.).

To suggest otherwise is ignorant and needlessly feverish.

Colossians says (last third of the first century) the gospel is already come "in all the world"

For the hope which is laid up for you in heaven, whereof ye heard before in the word of the truth of the gospel; Which is come unto you, as it is in all the world; and bringeth forth fruit, as it doth also in you, since the day ye heard of it, and knew the grace of God in truth:

-- Colossians 1:5f.

And this gospel of the kingdom shall be preached in all the world for a witness unto all nations; and then shall the end come.

-- Matthew 24:14