2 Corinthians 4:13

Overview - 2 Corinthians 4
He declares how he has used all sincerity and faithful diligence in preaching the gospel,
and how the troubles and persecutions which he daily endured for the same did redound to the praise of God's power,
12 to the benefit of the church,
16 and to the apostle's own eternal glory.
Treasury of Scripture Knowledge

2 Corinthians 4:13  (King James Version)
We having the same spirit of faith, according as it is written, I believed, and therefore have I spoken; we also believe, and therefore speak;

the same
Acts 15:11 ; Romans 1:12 ; 1 Corinthians 12:9 ; Hebrews 11:1-40 ; 2 Peter 1:1

I believed
Psalms 116:10

we also
3:12 Proverbs 21:28