Charles Ellicott Commentary Exodus 19:5

"Now therefore, if ye will obey my voice indeed, and keep my covenant, then ye shall be mine own possession from among all peoples: for all the earth is mine:" — Exodus 19:5 (ASV)

A peculiar treasure. —The Hebrew sĕgullah is from a root, found in Chaldee, meaning “to earn” or “acquire.” It primarily signifies some valuable possession that the owner has acquired by his own efforts (compare 1 Chronicles 29:3, where the English Version translates it as “mine own proper good.”).

God views the Israelites as made His own by the long series of mighty works done for their deliverance, by which He is sometimes said to have “redeemed” (Exodus 6:6; Exodus 15:13) or “purchased” them (Exodus 15:16). The word sĕgullah is used here for the first time. Later, it becomes an epitheton usitatum of Israel (Deuteronomy 14:2; Deuteronomy 26:18; Psalms 135:4; Malachi 3:17; and compare also Titus 2:14; 1 Peter 2:9).

Above all people: for all the earth is mine. —While claiming a peculiar right in Israel, God does not mean to separate Himself from the other nations, to cease to care for them, or give them up to their own devices. He is always the Most High over all the earth (Psalms 83:18), a light to lighten the Gentiles, one who judges the people righteously, and governs all the nations upon earth (Psalms 67:4). Israel’s prerogative does not rob them of their birthright. He is the favored son; but they, too, are, all of them, children of the Most High (Psalms 82:6).