“You will have
Joy
And gladness.
Many people
Will rejoice
At his birth.”
καὶ ἔσται χαρά σοι καὶ ἀγαλλίασις, καὶ πολλοὶ ἐπὶ τῇ γενέσει αὐτοῦ χαρήσονται
Luke had the angel state the obvious. Zechariah would have joy and gladness (καὶ ἔσται χαρά σοι καὶ ἀγαλλίασις). The Greek word χαρά for joy can also mean grace. Many people would rejoice at this birth of John (καὶ πολλοὶ ἐπὶ τῇ γενέσει αὐτοῦ χαρήσονται). This would be a happy graced moment for him and many others. The birth of a child in any family is very happy moment.
Eugene Finnegan Bible Project 