Theophylact of Ohrid — as excerpted in the Catena Aurea on Luke 6:37-38

“But some one will put the subtle question, “If the return is made overabundantly, how is it the same measure?” to which we answer, that He said not, “In just as great a measure shall it be measured to you again, but in the same measure.” For he who has shewn mercy, shall have mercy shewn unto him, and this is measuring again with the same measure; but our Lord spoke of the measure running over, because to such a one He will shew mercy a thousand times. So also in judging; for he that judges and afterwards is judged receives the same measure. But as far as he was judged the more severely that he judged one like unto himself, was the measure running over.”