Midrasch zu Bereschit 30:30

Rab Huna said: Everything is revealed and foreseen before the Holy One, blessed be He. Before Jacob came to Haran, what did the Holy One, blessed be He, do? He sent a plague among the sheep of Laban, and few were left out of many, and Rachel was tending these, as it is said, "Rachel came with her father's sheep; for she kept them" (Gen. 29:9). Whence do we know that few remained of the many? Because it is said, "And Jacob fed the rest of Laban's flocks" (Gen. 30:86), "the rest" (which remained) after the plague, in order to increase and multiply Laban's flocks at the feet of Jacob. Hence (the sages) said: Sometimes the foot of man destroys the house, and sometimes the foot of man blesses the house, as it is said, "And the Lord hath blessed thee at my foot" (Gen. 30:80). Likewise Laban said to Jacob: "I have divined that the Lord hath blessed me for thy sake" (Gen. 30:27).