In Talmud Berachot end of 14A, beginning of 14B, a reason is given why one does not make an interruption between "Ani Hashem Elokeichem" of the end of Shema, and "Emet":
א"ר אבהו א"ר יוחנן הלכה כר' יהודה דאמר בין אלהיכם לאמת ויציב לא יפסיק א"ר אבהו א"ר יוחנן מאי טעמיה דרבי יהודה דכתיב וה' אלהים אמת
Because there is a verse in Yirmiyahu 10:10 which says "וה' אלהים אמת", we therefore do not make a break between "אלהיכם" and " אמת ויציב" when saying Shema:
וַיהֹוָה אֱלֹהִים אֱמֶת הוּא אֱלֹהִים חַיִּים וּמֶלֶךְ עוֹלָם מִקִּצְפּוֹ תִּרְעַשׁ הָאָרֶץ וְלֹא יָכִלוּ גוֹיִם זַעְמוֹ:
But the Lord God is true; He is a living God and the King of the world; from His anger the earth quakes, and the nations cannot contain His fury.
I don't understand this proof, and I'm looking for an explanation. What is the proof from the verse in Yirmiyahu? How does the fact that it says something similar in Yirmiyahu necessitate it in Shema?
