(א) בִּשְׁנַת־מוֹת֙ הַמֶּ֣לֶךְ עֻזִּיָּ֔הוּ וָאֶרְאֶ֧ה אֶת־אדושם יֹשֵׁ֥ב עַל־כִּסֵּ֖א רָ֣ם וְנִשָּׂ֑א וְשׁוּלָ֖יו מְלֵאִ֥ים אֶת־הַהֵיכָֽל׃ (ב) שְׂרָפִ֨ים עֹמְדִ֤ים ׀ מִמַּ֙עַל֙ ל֔וֹ שֵׁ֧שׁ כְּנָפַ֛יִם שֵׁ֥שׁ כְּנָפַ֖יִם לְאֶחָ֑ד בִּשְׁתַּ֣יִם ׀ יְכַסֶּ֣ה פָנָ֗יו וּבִשְׁתַּ֛יִם יְכַסֶּ֥ה רַגְלָ֖יו וּבִשְׁתַּ֥יִם יְעוֹפֵֽף׃ (ג) וְקָרָ֨א זֶ֤ה אֶל־זֶה֙ וְאָמַ֔ר קָד֧וֹשׁ ׀ קָד֛וֹשׁ קָד֖וֹשׁ יי צְבָא֑וֹת מְלֹ֥א כָל־הָאָ֖רֶץ כְּבוֹדֽוֹ׃ (ד) וַיָּנֻ֙עוּ֙ אַמּ֣וֹת הַסִּפִּ֔ים מִקּ֖וֹל הַקּוֹרֵ֑א וְהַבַּ֖יִת יִמָּלֵ֥א עָשָֽׁן׃ (ה) וָאֹמַ֞ר אֽוֹי־לִ֣י כִֽי־נִדְמֵ֗יתִי כִּ֣י אִ֤ישׁ טְמֵֽא־שְׂפָתַ֙יִם֙ אָנֹ֔כִי וּבְתוֹךְ֙ עַם־טְמֵ֣א שְׂפָתַ֔יִם אָנֹכִ֖י יוֹשֵׁ֑ב כִּ֗י אֶת־הַמֶּ֛לֶךְ יי צְבָא֖וֹת רָא֥וּ עֵינָֽי׃ (ו) וַיָּ֣עָף אֵלַ֗י אֶחָד֙ מִן־הַשְּׂרָפִ֔ים וּבְיָד֖וֹ רִצְפָּ֑ה בְּמֶ֨לְקַחַ֔יִם לָקַ֖ח מֵעַ֥ל הַמִּזְבֵּֽחַ׃ (ז) וַיַּגַּ֣ע עַל־פִּ֔י וַיֹּ֕אמֶר הִנֵּ֛ה נָגַ֥ע זֶ֖ה עַל־שְׂפָתֶ֑יךָ וְסָ֣ר עֲוֺנֶ֔ךָ וְחַטָּאתְךָ֖ תְּכֻפָּֽר׃ (ח) וָאֶשְׁמַ֞ע אֶת־ק֤וֹל אדושם אֹמֵ֔ר אֶת־מִ֥י אֶשְׁלַ֖ח וּמִ֣י יֵֽלֶךְ־לָ֑נוּ וָאֹמַ֖ר הִנְנִ֥י שְׁלָחֵֽנִי׃
(1) In the year that King Uzziah died, I beheld my Lord seated on a high and lofty throne; and the skirts of His robe filled the Temple. (2) Seraphs stood in attendance on Him. Each of them had six wings: with two he covered his face, with two he covered his legs, and with two he would fly. (3) And one would call to the other, “Holy, holy, holy! The LORD of Hosts! His presence fills all the earth!” (4) The doorposts would shake at the sound of the one who called, and the House kept filling with smoke. (5) I cried, “Woe is me; I am lost! For I am a man of unclean lips And I live among a people Of unclean lips; Yet my own eyes have beheld The King LORD of Hosts.” (6) Then one of the seraphs flew over to me with a live coal, which he had taken from the altar with a pair of tongs. (7) He touched it to my lips and declared, “Now that this has touched your lips, Your guilt shall depart And your sin be purged away.” (8) Then I heard the voice of my Lord saying, “Whom shall I send? Who will go for us?” And I said, “Here am I; send me.”
Notice that Isaiah observes G-d from a distance and G-d is not paying any attention to him. By chance he spoke up while watching the goings-on in Heaven. Then a seraph used tongs to pick up a live coal to touch Isaiah's lips, thus bestowing the power of prophecy. Still without acknowledging Isaiah's presence, G-d asks whom G-d shall send as a prophet. Isaiah has to call out to G-d asking to be that prophet. Compare to the following interaction between G-d and Jeremiah.
(ד) וַיְהִ֥י דְבַר־יי אֵלַ֥י לֵאמֹֽר׃
(ה) בְּטֶ֨רֶם אצורך [אֶצָּרְךָ֤] בַבֶּ֙טֶן֙ יְדַעְתִּ֔יךָ וּבְטֶ֛רֶם תֵּצֵ֥א מֵרֶ֖חֶם הִקְדַּשְׁתִּ֑יךָ נָבִ֥יא לַגּוֹיִ֖ם נְתַתִּֽיךָ׃ (ו) וָאֹמַ֗ר אֲהָהּ֙ אדושם יי הִנֵּ֥ה לֹא־יָדַ֖עְתִּי דַּבֵּ֑ר כִּי־נַ֖עַר אָנֹֽכִי׃ (פ) (ז) וַיֹּ֤אמֶר יי אֵלַ֔י אַל־תֹּאמַ֖ר נַ֣עַר אָנֹ֑כִי כִּ֠י עַֽל־כָּל־אֲשֶׁ֤ר אֶֽשְׁלָחֲךָ֙ תֵּלֵ֔ךְ וְאֵ֛ת כָּל־אֲשֶׁ֥ר אֲצַוְּךָ֖ תְּדַבֵּֽר׃ (ח) אַל־תִּירָ֖א מִפְּנֵיהֶ֑ם כִּֽי־אִתְּךָ֥ אֲנִ֛י לְהַצִּלֶ֖ךָ נְאֻם־יי (ט) וַיִּשְׁלַ֤ח יי אֶת־יָד֔וֹ וַיַּגַּ֖ע עַל־פִּ֑י וַיֹּ֤אמֶר יי אֵלַ֔י הִנֵּ֛ה נָתַ֥תִּי דְבָרַ֖י בְּפִֽיךָ׃ (י) רְאֵ֞ה הִפְקַדְתִּ֣יךָ ׀ הַיּ֣וֹם הַזֶּ֗ה עַל־הַגּוֹיִם֙ וְעַל־הַמַּמְלָכ֔וֹת לִנְת֥וֹשׁ וְלִנְת֖וֹץ וּלְהַאֲבִ֣יד וְלַהֲר֑וֹס לִבְנ֖וֹת וְלִנְטֽוֹעַ׃ (פ)
(4) The word of the LORD came to me:
(5) Before I created you in the womb, I selected you; Before you were born, I consecrated you; I appointed you a prophet concerning the nations. (6) I replied: Ah, Lord GOD! I don’t know how to speak, For I am still a boy. (7) And the LORD said to me: Do not say, “I am still a boy,” But go wherever I send you And speak whatever I command you. (8) Have no fear of them, For I am with you to deliver you —declares the LORD. (9) The LORD put out His hand and touched my mouth, and the LORD said to me: Herewith I put My words into your mouth. (10) See, I appoint you this day Over nations and kingdoms: To uproot and to pull down, To destroy and to overthrow, To build and to plant.
In this passage, G-d speaks very intimately of Jeremiah saying he was chosen even before in his mother's womb. G-d speaks directly to Jeremiah, whether Jeremiah desired it or not. Then, in verse nine G-d touches Jeremiah's lips to bestow the power of prophecy. Compare this intimate act to that of Isaiah's acquisition of prophecy in which Isaiah's lips were touched by a coal, held by tongs, held by a seraph (not even G-d).