In 1 Thessalonians 2:19, Paul asks what is his hope, joy, and crown — the immediate foundation for calling them his glory and joy.

2 Corinthians 1:14 explicitly says the same thing: on the Lord's day, Paul and the church will be each other's pride — directly paralleling the glory here.

In Philippians 4:1, Paul calls the Philippians his 'joy and crown' — an exact parallel to the Thessalonians being his glory and joy.

Proverbs 17:6 calls grandchildren a crown to the aged — the same metaphor of children as honor, now applied to Paul's spiritual children.

Daniel 12:3 promises that those who lead many to righteousness will shine like stars — Paul's converts are his own glory and reward.

Proverbs 23:15 says a father's heart gladdens at his son's wisdom — akin to Paul's joy in his spiritual children as his glory.