For he was crucified in weakness, but lives by the power of God. For we also are weak in him, but in dealing with you we will live with him by the power of God” (2 Cor. 13:4).

The ‘super-apostles’ in Corinth despised Paul ‘weakness’ (‘his bodily presence is weak’, 2 Cor 10:10). They said he was ‘unimpressive’ (2 Cor 10:10). Paul responds by indicating that it is in his weakness that he is an analogy of Christ to men. God’s power does not necessarily destroy weakness; indeed, his saving power is expressed through the weakness of the cross.

Careful attention is required in order to feel the weight of Paul’s language here. He does not say: ‘We are weak in ourselves, but we are strong in Christ.’…Rather, Paul has a different perspective: bound by the Spirit to Christ crucified and risen, he is weak in Christ, as well as powerful in him….Paul’s weakness is not a motivation for seeking union with Christ in order that he might be strong; it is the direct consequence, implication and outworking of that very union in the Spirit.

This, then, is the way of sanctification, because it is the way of Christiformity, and ultimately the way in which the restoration to the divine glory-image is complete.

~ Sinclair B. Ferguson, The Holy Spirit, p. 170-171