# I wrote as I did

Some scholars believe this refers to the letter known as First Corinthians. Other scholars believe this refers to a letter Paul wrote after the letter known as First Corinthians and before this letter. Alternate translation: "I wrote as I did in my previous letter" 

# I might not be hurt by those who should have made me rejoice

"those who should have made me rejoice might not hurt me" 

# my joy is the same joy you all have

"what gives me joy is what gives you joy, too"