The Mishkan stirring the tribes who uphold the world

בפסוק ביום כלות משה להקים כו'.

On the verse: "On the day that Moshe finished setting up [the Mishkan]," etc.

The Sefas Emes opens on the verse describing the completion and erecting of the Mishkan.

ובמד' מי הקים כו' אפסי ארץ כו' אפסי ארץ הם השבטים שהם גבולי עולם ומיד כשהקים המשכן הרגישו נשיאי ישראל ונתקרבו אל הבורא ית' כמ"ש ויקרבו נשיאי ישראל כו' ועיין במ"א מזה:

And in the Midrash: "Who raised up... the ends of the earth," etc. — "the ends of the earth" are the tribes, who are the boundaries of the world; and immediately when the Mishkan was erected, the princes of Yisrael felt it and drew near to the Creator, blessed be He, as it is written, "And the princes of Yisrael drew near," etc.; and see elsewhere regarding this.

The Midrash identifies "the ends of the earth" with the tribes of Yisrael, who form the very boundaries and supports of the world. The moment the Mishkan stood, the nesi'im (princes) of the tribes sensed the new spiritual reality and were stirred to come close to Hashem, bringing their offerings — for the raising of the Mishkan awakened the deepest roots of the nation, which uphold all of creation.

Summary: The tribes of Yisrael are called "the ends of the earth" because they are the boundaries and supports of the world. The moment the Mishkan was erected, the princes of the tribes immediately sensed the new spiritual presence and were moved to draw near to Hashem with their offerings, showing that the establishment of the Mishkan awakened the foundational roots of Bnei Yisrael that sustain all of creation.