Isn't worshipping Jesus idolatry?

Idolatry is worshipping something created in place of God. Messianic Jews worship only the God of Israel, and believe Yeshua is that God made known, not a second god.

The fear is real and comes from a good place: the first commandment. Maimonides counted belief in God's absolute unity among the foundations of faith, and many Jewish people have been taught that Christianity breaks it.

Messianic Jews say the Shema with all their heart. The question isn't whether God is one, but how the one God reveals himself. In the Tanakh God appears to Abraham as a man (Genesis 18), the angel of the LORD speaks as God and is worshipped (Exodus 3, Judges 13), and God's Word and Spirit act as God.

Yeshua accepted worship only because he claimed to be the one God of Israel come in person. If he isn't, it would be idolatry. If he is, it's the most Jewish worship there is. That's the claim to weigh.

In the Scriptures

⁴שְׁמַ֖ע יִשְׂרָאֵ֑ל יְהוָ֥ה אֱלֹהֵ֖ינוּ יְהוָ֥ה ׀ אֶחָֽד׃

⁴HEAR, O ISRAEL: THE LORD OUR GOD, THE LORD IS ONE.
Deuteronomy 6:4 (Hebrew & JPS 1917)

¹וַיֵּרָ֤א אֵלָיו֙ יְהוָ֔ה בְּאֵלֹנֵ֖י מַמְרֵ֑א וְה֛וּא יֹשֵׁ֥ב פֶּֽתַח־הָאֹ֖הֶל כְּחֹ֥ם הַיּֽוֹם׃ ²וַיִּשָּׂ֤א עֵינָיו֙ וַיַּ֔רְא וְהִנֵּה֙ שְׁלֹשָׁ֣ה אֲנָשִׁ֔ים נִצָּבִ֖ים עָלָ֑יו וַיַּ֗רְא וַיָּ֤רָץ לִקְרָאתָם֙ מִפֶּ֣תַח הָאֹ֔הֶל וַיִּשְׁתַּ֖חוּ אָֽרְצָה׃

¹And the LORD appeared unto him by the terebinths of Mamre, as he sat in the tent door in the heat of the day; ²and he lifted up his eyes and looked, and, lo, three men stood over against him; and when he saw them, he ran to meet them from the tent door, and bowed down to the earth,
Genesis 18:1-2 (Hebrew & JPS 1917)

²וַ֠יֵּרָא מַלְאַ֨ךְ יְהֹוָ֥ה אֵלָ֛יו בְּלַבַּת־אֵ֖שׁ מִתּ֣וֹךְ הַסְּנֶ֑ה וַיַּ֗רְא וְהִנֵּ֤ה הַסְּנֶה֙ בֹּעֵ֣ר בָּאֵ֔שׁ וְהַסְּנֶ֖ה אֵינֶ֥נּוּ אֻכָּֽל׃ ³וַיֹּ֣אמֶר מֹשֶׁ֔ה אָסֻֽרָה־נָּ֣א וְאֶרְאֶ֔ה אֶת־הַמַּרְאֶ֥ה הַגָּדֹ֖ל הַזֶּ֑ה מַדּ֖וּעַ לֹא־יִבְעַ֥ר הַסְּנֶֽה׃ ⁴וַיַּ֥רְא יְהוָ֖ה כִּ֣י סָ֣ר לִרְא֑וֹת וַיִּקְרָא֩ אֵלָ֨יו אֱלֹהִ֜ים מִתּ֣וֹךְ הַסְּנֶ֗ה וַיֹּ֛אמֶר מֹשֶׁ֥ה מֹשֶׁ֖ה וַיֹּ֥אמֶר הִנֵּֽנִי׃ ⁵וַיֹּ֖אמֶר אַל־תִּקְרַ֣ב הֲלֹ֑ם שַׁל־נְעָלֶ֨יךָ֙ מֵעַ֣ל רַגְלֶ֔יךָ כִּ֣י הַמָּק֗וֹם אֲשֶׁ֤ר אַתָּה֙ עוֹמֵ֣ד עָלָ֔יו אַדְמַת־קֹ֖דֶשׁ הֽוּא׃ ⁶וַיֹּ֗אמֶר אָנֹכִי֙ אֱלֹהֵ֣י אָבִ֔יךָ אֱלֹהֵ֧י אַבְרָהָ֛ם אֱלֹהֵ֥י יִצְחָ֖ק וֵאלֹהֵ֣י יַעֲקֹ֑ב וַיַּסְתֵּ֤ר מֹשֶׁה֙ פָּנָ֔יו כִּ֣י יָרֵ֔א מֵהַבִּ֖יט אֶל־הָאֱלֹהִֽים׃

²And the angel of the LORD appeared unto him in a flame of fire out of the midst of a bush; and he looked, and, behold, the bush burned with fire, and the bush was not consumed. ³And Moses said: ‘I will turn aside now, and see this great sight, why the bush is not burnt.’ ⁴And when the LORD saw that he turned aside to see, God called unto him out of the midst of the bush, and said: ‘Moses, Moses.’ And he said: ‘Here am I.’ ⁵And He said: ‘Draw not nigh hither; put off thy shoes from off thy feet, for the place whereon thou standest is holy ground.’ ⁶Moreover He said: ‘I am the God of thy father, the God of Abraham, the God of Isaac, and the God of Jacob.’ And Moses hid his face; for he was afraid to look upon God.
Exodus 3:2-6 (Hebrew & JPS 1917)