Albert Barnes Commentary John 17:13

"But now I come to thee; and these things I speak in the world, that they may have my joy made full in themselves." — John 17:13 (ASV)

My joy fulfilled, etc. See Barnes on John 15:11.

The expression "my joy" here probably refers to the joy of the apostles respecting the Saviour—the joy which would result from his resurrection, ascension, and intercession in heaven.