For power is perfected in weakness ... for when I am weak, then I am strong (2 Corinthians 12:9, 10)
The conflicting anguish and joyful honor for every Christian is the weakness/strength tension. Strength (power of Christ, 12:9) exhibited in endurance. Weaknesses (insults, distresses, persecutions, difficulties, 12:10) groaned.
The text does not say, having been weak I am made strong, as if this was sequential growth in Christ. The text does not say, once I was weak but now I am strong, as if a one-time event that never reoccurs produces a strength that never fades.
No, the Word of Jesus Christ declares that weakness and strength, infirmity and power, are contemporaries. They exist at the very same moment. When I am weak, then I am strong. Afflicted, but not ultimately crushed. Perplexed, but not resting in despair. Persecuted, but never abandoned by the Lord. Struck, but never destroyed. We bear in our body Jesus’ death presently so that, concurrently Jesus’ life is made evident through the members of our body (2 Corinthians 4:7-12). Therefore, believers must mature in our understanding that growing in the grace of His strength means a corresponding growth in our weaknesses.
Eternal life is joyful anguish in this dark world. Joy in Christ, by Christ, and through Christ is our endurance (Hebrews 12:2) and our strength (Nehemiah 8:10). Jesus spoke in order that His joy may abide in us in its fullness (John 15:11). Anguish exists because no man naturally glories in their weaknesses. No one naturally rejoices in their cross of His affliction and reproach.
When I am weak, then I am strong. The frustrations and anguish of our exposed weaknesses are turned into the joy of beholding the power of Christ in our endurance and ultimately, our resurrection. So, as we grow weak in Christ, rejoice in the growth of His power being manifested in your body.