Sforno on Genesis 27:39/ספורנו על בראשית כ״ז:ל״ט

1הנה משמני הארץ יהיה מושבך, I am able to bless you, assuring you that you and your descendants will reside in fruitful areas of the earth, even if they will be marginally subservient to your brother.

2ומטל השמים מעל, ועל חאבך תחיה, you will be able to live on the blessings provided by the dew without needing rainfall or having to toil the earth; you will live by your sword in times of war. even though at the same time you may be in a state of subservience to your brother and even engage in war as a mercenary on behalf of your brother or someone else. From this it follows that if you were to complain about unreasonable harshness of your brother’s yoke, כאשר תריד, and would want to ופרקת עלו מעל צוארך, “shake off his yoke from around your neck.,” i.e. revert to a different lifestyle, such as engaging in agriculture, know that then you will never become free from subservience to your brother or to someone else.