When we perform a mitzvah we hug God (and He hugs us) as it were. When we learn the sweet words of Torah we kiss. In prayer we cling.
Isaac prayed for children in one corner of the room and Rebecca in another corner. As the prayers ascended they united and became one.
Rebecca's prayer augmented the potency of Isaac's prayer. Below, on the physical plane, she could then conceive and bear children.
