King James Version (KJV)
Then they said to Jeremiah, The LORD be a true and faithful witness between us, if we do not even according to all things for the which the LORD thy God shall send thee to us.
Modern English
Then they said to Jeremiah, “May Yahweh be a true and faithful witness among us, if we don’t do according to all the word with which Yahweh your God sends you to tell us.
Hebrew
וְהֵ֙מָּה֙ אָמְר֣וּ אֶֽל־יִרְמְיָ֔הוּ יְהִ֤י יְהוָה֙ בָּ֔נוּ לְעֵ֖ד אֱמֶ֣ת וְנֶאֱמָ֑ן אִם־לֹ֡א כְּֽכָל־הַ֠דָּבָר אֲשֶׁ֨ר יִֽשְׁלָחֲךָ֜ יְהוָ֧ה אֱלֹהֶ֛יךָ אֵלֵ֖ינוּ כֵּ֥ן נַעֲשֶֽׂה׃
vhemah ʾamrv ʾel-yirmyahv yhiy yhvah banv lʿed ʾemet vneʾeman ʾim-loʾ kkal-hadabar ʾasher yishlaḥaka yhvah ʾeloheyka ʾeleynv ken naʿasheh