John Gill Commentary Mark 12:9

"What therefore will the lord of the vineyard do? he will come and destroy the husbandmen, and will give the vineyard unto others." — Mark 12:9 (ASV)

What shall therefore the Lord of the vineyard do ?
&c.] The Arabic and Ethiopic versions add, to them; that is, to the husbandmen, as is expressed in (Matthew 21:40) , (See Gill on Matthew 21:40):

he will come and destroy the husbandmen, and will give the vineyard
unto others .
As the former clause contains a question put by Christ upon his having finished the parable, this is an answer to it, given by the chief priests, Scribes, and elders, in whose presence, and for whose sake it was delivered; (See Gill on Matthew 21:41).