Charles Ellicott Commentary Isaiah 65:24

"And it shall come to pass that, before they call, I will answer; and while they are yet speaking, I will hear." — Isaiah 65:24 (ASV)

Before they call ... — In one's experience with others, and often currently in one's relationship with God, there is an interval between prayer and the answer. In the new Jerusalem the two would be simultaneous, or the answer would anticipate the prayer.