John Calvin Commentary Isaiah 65:19

"And I will rejoice in Jerusalem, and joy in my people; and there shall be heard in her no more the voice of weeping and the voice of crying." — Isaiah 65:19 (ASV)

And I will be glad in Jerusalem. He expresses more than in the preceding verse; for by these words he means that he not only will give people reason for rejoicing, but will even be a participant with them in that joy. So great is his love toward us, that he delights in our prosperity no less than if he enjoyed it with us.

And thus we obtain no small confirmation of our faith when we learn that God is moved, and so powerfully moved, by such an affection toward us. If we are in painful and distressed circumstances, he says that he is affected by grief and sorrow; and, on the other hand, if our condition is pleasant and comfortable, he says that he takes great pleasure in our prosperity. Thus, we have also previously seen that the Spirit of the Lord is sad and vexed (Isaiah 63:10), when that order which he demands and approves is overturned and confounded; and in another passage he presents himself as a husband who is satisfied with the love of his wife (Isaiah 62:5).