Therefore the Lord assured him by an oath that the nations would be blessed through his posterity: Therefore (“And so” in Good News Translation, Contemporary English Version) implies that since Abraham was found faithful, the Lord made him this “solemn promise” (Good News Translation). The Lord is literally “he,” but Revised Standard Version spells out the pronoun for clarity. The nations refers to nations other than Israel. Good News Translation “the world” is a good equivalent. Other possibilities are “the people of all nations” and “all the people of the world.” Posterity refers to “descendants.” That the nations would be blessed through his posterity may be rendered “that his descendants would bring great benefits to all the people of the world.”

That he would multiply him like the dust of the earth: This is a second part of the “solemn promise.” The Lord promises that Abraham will have so many descendants that one could no more count them than one could count particles of dust. So we may translate “that their number would be countless, like the dust of the earth” (Good News Translation) or “They would be more numerous than specks of dust on the earth.” (Some translators may find the image “grains of sand” more appropriate than dust; see Gen 22.17.)

And exalt his posterity like the stars: This is a third part of the “solemn promise.” To exalt is literally to elevate; the figure here says that God will raise Abraham’s descendants as high as the stars. This is very difficult in English, and Good News Translation abandons the simile and simply states the meaning: “that they would be honored more than any other people on earth.”

And cause them to inherit from sea to sea: This is a fourth part of the “solemn promise.” God promises Abraham that his descendants will have (inherit) a land of their own. We cannot be certain exactly what is meant by from sea to sea. In Exo 23.31 there are more specific references: “from the Red Sea to the sea of the Philistines” (New Revised Standard Version), which Good News Translation translates “from the Gulf of Aqaba to the Mediterranean Sea.” See also Deut 11.24; Josh 1.4. Our passage here more closely resembles Psa 72.8 and Zech 9.10, where a vague “from sea to sea” may serve simply to express the greatness of Israel in an exaggerated figure of speech. For the whole line Good News Translation has “and that their land would extend from sea to sea,” and Contemporary English Version says “and they would be given land from sea to sea.” We might also express this as “and he [the Lord] would give them land that would extend from sea to sea.”

And from the River to the ends of the earth: The River in the Old Testament usually means the Euphrates River (in modern Iraq). The ends of the earth (literally “the end of the earth”) may simply refer to the shore of the Mediterranean Sea, where the land of Israel ended. There is really no evidence that the promise to Abraham was ever understood as meaning the whole world. If ben Sira were pressed here, he would probably say that this passage refers to the territory from the Red Sea to the Mediterranean Sea and eastward as far as the Euphrates River. Trying to be this precise in translation, however, may miss the real effect of the author’s sweeping exaggeration.

An alternative model for this verse is:

• And so, the Lord assured Abraham with a strong [or, solemn] promise that his descendants would be a blessing [or, bring great benefits] to all the people of the world; that they would be more numerous than the particles of dust on the earth; that they would be more honored [or, receive more honor] than any other people on earth; and that he [the Lord] would give them land that would extend from sea to sea, and from the Euphrates River to the ends of the earth.

Quoted with permission from Bullard, Roger A. and Hatton, Howard A. A Handbook on Sirach. (UBS Helps for Translators). New York: UBS, 2008. For this and other handbooks for translators see here.