In this week’s Torah portion we read of the account of Noah planting a vineyard and after drinking of some of its fruits becomes intoxicated. He then uncovers himself. Ham enters, sees what his father has done and goes and tells his other two brothers.
Shem and Japheth immediately seek to cover their father’s shame:
Then Shem and Japheth took a garment, laid it on both their shoulders, and walked backward and covered the nakedness of their father. Their faces were turned backward, and they did not see their father’s nakedness. (Genesis 9:22-23)
When Noah awakes from his slumber and realizes what has been done he curses Ham for his disrespect: “Cursed be Canaan; a servant of servants shall he be to his brothers” (Genesis 9:25). At the same time he blesses Shem and Japheth:
Blessed be the LORD, the God of Shem; and let Canaan be his servant. May God enlarge Japheth, and let him dwell in the tents of Shem, and let Canaan be his servant. (Genesis 9:26-27)
It is curious what Noah says here. If both the sons sought to cover up their father and show him honor, why does Shem get a greater blessing? Rashi weighs in:
“And Shem and Japheth took (וַיִּקַּח)”: It does not say וַיִּקְחוּ (the plural form), but וַיִּקַּח, the singular form. This teaches us about Shem, that he exerted himself to fulfill the commandment more than Japheth. Therefore, his sons merited a tallit with fringes, and Japheth merited burial for his sons, as it is said (Ezekiel 39:11): “I will give Gog a place there as a grave in Israel.” 
In turn while both sons are rewarded Shem gets the greater reward because he seems to have put more effort into covering up his father than Japheth did. According to Jewish tradition both sons are rewarded measure for measure. Because they covered their father they each received a reward in connection with a covering. Japheth’s descendants are to be buried in Israel and Shem’s descendants (the Jewish people) will receive the commandment of tzitzit on their garments.
Midrash Tanchuma relates a similar tradition:
What did the Holy One, blessed is He, give him in return? He recompensed Shem by rewarding him with the commandment of tzitzit in his garment with which he covered himself. And the Japheth he gave the right of burial in the Land of Israel. (Midrash Tanchuma, Noach 15) 
This midrash seems to say that Shem himself received the mitzvah of tzitzit and not merely that it was given to his descendants (i.e., Israel). Also, in the original version of this midrash we find “the commandment of techelet” instead of “the commandment of tzitzit.” Techelet is the special blue dyed thread to be added to the white tzitzit. 
So what was Shem’s blessing? Did he receive the commandment of tzitzit or was it his descendants? Was it the commandment of tzitzit in general or specifically the techelet blue?
Rabbi David Katz takes this confusion as an opportunity to move away from the straight forward interpretation and create a metaphorical picture. He has suggested that symbolically the white tzitzit represents the righteous of the nations seen in Shem who was not Jewish, who have attached themselves to the nation of Israel. In turn, the techelet blue represents the nation of Israel (Shem’s descendants) who received this commandment in Numbers 15 and were a royal priesthood to the nations. Israel was called to be a kingdom of priests and techelet is the color of the priesthood.  In turn the full tzitzit with the white threads and the techelet blue metaphorically represents Israel along with the nations that have joined themselves to the Jewish people.
The idea of the nations joining themselves to Israel is actually in Noah’s blessing to Shem: “May God enlarge Japheth, and let him dwell in the tents of Shem.” Japheth represents those of the nations who join themselves to Shem, who represents the Jewish people. The targumic paraphrase makes this even more specific:
And he said, “Blessed be the Lord, the God of Shem, whose work is righteous; and therefore shall Canaan be servant unto him. The Lord shall beautify the borders of Japheth, and his sons shall be proselyted and dwell in the schools of Shem, and Canaan shall be a servant to them.” (Genesis 9:27 Targum Pseudo-Jonathan)
According to this Targum the people of the nations will fall into two categories in the Messianic Era. There will be those who have turned to the God of Israel and join in with the Jewish people and there will be those who will be conquered and in turn subjected to become servants to the nation of Israel. The prophets paint a similar picture:
Thus says the LORD of hosts: In those days ten men from the nations of every tongue shall take hold of the robe of a Jew, saying, “Let us go with you, for we have heard that God is with you.” (Zechariah 8:23)
And the peoples will take them and bring them to their place, and the house of Israel will possess them in the LORD’s land as male and female slaves. They will take captive those who were their captors, and rule over those who oppressed them. (Isaiah 14:2)
Gentiles in Messiah Yeshua are dwelling in the tents of Shem so to speak. They have chosen not to be slaves of Israel but to become partners with them in working toward the kingdom of heaven. They are the white threads amongst techelet blue priesthood of Israel. Shem’s descendants are the Jewish people and by accepting a Jewish Messiah Gentiles have aligned themselves with the Jewish people as well. Indeed they can also say “Blessed is the God of Shem!”
- Translation from: http://www.chabad.org/library/bible_cdo/aid/8173/jewish/Chapter-9.htm#showrashi=true.
- Translation from: https://www.judaicapress.com/products/metsudah-midrash-tanchuma-8-vol. Also: “Therefore Shem was granted a tallit and Japheth a pallium” (Genesis Rabbah 36:6).
- Numbers 15:38.
- From Torah of Shem Part 3: https://www.youtube.com/watch?v=c7DgnB5mtkg&list=PLw2PB0CJC7HTTWOOdo_Re18oObQ4cNa1Z&index=3
- For example in Exodus 28, techelet is used in both the priests clothing and the fabric of the tabernacle.
Source: First Fruits of Zion