a joining word that ties an action to the reason or the goal behind it: because of, for the sake of, or so that
This is a small connecting word that never stands alone. In the text it always appears attached to the front of a phrase or clause, and its whole job is to point at the reason something happens. It can face in either direction. Sometimes it looks backward to a cause ("cursed is the ground because of you"), and sometimes it looks forward to a goal ("so that your soul may bless me").
Which direction it faces usually depends on what follows it. When it introduces a person or a thing, it tends to look back and mean "because of" or "for the sake of" that person. When it introduces an action, it tends to look forward and mean "so that" or "in order that" the action may happen. It is the same word doing both, and a few verses hold both at once, where a cause and a purpose land on the very same thing.
One backward-looking use carries special weight. When God acts "for the sake of" a person, the word becomes the language of promise and of mercy shown on someone else's account. It is the word Abraham reaches for when he pleads that God spare a whole city for the sake of a righteous few, and it anchors the refrain that God keeps his people "for the sake of" his servant David and "for the sake of" his own name. The nearest word to it is לְמַעַן, which leans more toward a forward goal, while a word like בִּגְלַל only ever looks back to a cause.
Two verses in the prophet Amos stretch it toward the world of buying and selling, where the poor are handed over "for a pair of sandals." Whether that is a genuine price or simply the ordinary "on account of" is a real question among scholars, noted on those verses below.
Nuances
Whether בַּעֲבוּר זֹאת is purposive ("for this very purpose") or general causal ("on account of this"); the same clause is quoted at Romans 9:17.
- majorityPurposive: "for this very purpose I raised you up"; Paul renders it this way at Romans 9:17 with a forward-looking phrase.; William H. C. Propp, Exodus 1-18, AB 2 (Doubleday, 1999), pp. 334-335; C. E. B. Cranfield, Romans, ICC (T&T Clark, 1979), 2:487-488
- minorityGeneral causal "on account of this," the neutral rendering reflected in the ancient Greek translation.; John William Wevers, Notes on the Greek Text of Exodus, SBLSCS 30 (Scholars, 1990)
Whether the word here means "at the price of / in exchange for," matching "for silver" in the parallel line about selling the poor, or simply the ordinary "for the sake of / on account of."
- contestedA price-or-exchange sense: the needy are sold at the price of a pair of sandals, parallel to being sold "for silver."; Shalom M. Paul, Amos, Hermeneia (Fortress, 1991), pp. 77-79; Andersen and Freedman, Amos, AB 24A (Doubleday, 1989), pp. 312-315
- contestedThe ordinary causal "for the sake of / on account of"; the sandal is a symbolic token of a legal transfer, not a market price.; Hans Walter Wolff, Joel and Amos, Hermeneia (Fortress, 1977), pp. 165-166
Whether the word here means "at the price of / in exchange for," matching "for silver" in the parallel line about buying the poor, or simply the ordinary "for the sake of / on account of."
- contestedA price-or-exchange sense: the needy are bought at the price of a pair of sandals, parallel to being bought "for silver."; Shalom M. Paul, Amos, Hermeneia (Fortress, 1991), pp. 257-261; Andersen and Freedman, Amos, AB 24A (Doubleday, 1989), pp. 312-315
- contestedThe ordinary causal "for the sake of / on account of"; the sandal is a symbolic token of a legal transfer, not a market price.; Hans Walter Wolff, Joel and Amos, Hermeneia (Fortress, 1977), pp. 165-166