Japheth's blessing consists of three parts.
(1) "God give spreading out to the spreader out" (Gen.: 9:27), or "God make it wide to the wide."
The play on the words "He makes wide" (Heb. japht) and the name Japheth should be reproduced in the translation.
Japheth was the father of the Medes (Heb. Madai, Gen. 10:2), and the Greeks, Romans, Persians, Indians (Aryans), Germans, Persians, Italians, French, Spaniards, Slavs and many others.
Taken together they are all styled "Indo-Germanic" (Aryans).
(2) "Let him dwell in the tents of Shem" (Gen 9: 27).
- dwelling in his tents can signify nothing else than partaking in his faith and the reception of the Japhethites into the fellowship of his spiritual salvation.
- in fact the blessing promised to Shem has reached less to Hamitic and principally to Japhetic peoples (Gal. 3:14)
- Thus already Jerome, Calvin, Luther, almost all the church fathers, Lange, Keil, Delitzsch, and others.
- historically carried out in the person of the Roman Cornelius; and thus, as regards the fulness of salvation, by this means a Japhethite the first from among the nations, was allowed to enter the tents of Shem without joining the nation of Israel
- then a further turning-point in the same direction was that other vision of Paul, when in Troas he saw a man of Macedonia who called to him: "Come over, and help us" (Acts 16: 9, 10)
- bringing of the message of salvation over to Europe
(3) "And let Canann be his servant" (Gen. 9: 27).
- well, you know the history
The descendants of Ham (= heat) inhabited the hot lands; the sons of Japheth (extension) spread themselves out over the earth, and the generations of Canaan (the subdued) had to submit themselves to Japheth and Shem.
Dawn of World Redemption-Part II Chap.6