Sforno on Genesis 29:10/ספורנו על בראשית כ״ט:י׳

1כאשר ראה יעקב את רחל, until he had met Rachel Yaakov had not been interested to get involved in the problem of rolling the rock off the top of the well. He had been afraid that if he helped the three shepherds would only be concerned with watering their own flocks without waiting around to assist any other shepherds.