A.T. Robertson Commentary Matthew 25:21

"His lord said unto him, Well done, good and faithful servant: thou hast been faithful over a few things, I will set thee over many things; enter thou into the joy of thy lord." — Matthew 25:21 (ASV)

The joy of thy lord (την χαριν του κυριου σου). The word χαρα or joy may refer to the feast on the master's return. So in verse 23.