Deuteronomy 33:24. Let him be acceptable to his brethren, and let him dip his foot in oil.
This refers to the primitive method of treading the olives in order to express the oil. It is not now practiced, and could only be done when the olives were very soft. There is a similar allusion in Micah 6: 15. See also the note on Job 29:6 (#418).