There is a scripture in the Tanakh where G-d clearly says a convert to Judaism is to be treated,as if he were born a Jew. I've seen it but can't seem to find it. Perhaps one more knowledgeable then I would know. Thank you
Does Vayikro (Leviticus) 19:34 suit?
כְּאֶזְרָח מִכֶּם יִהְיֶה לָכֶם הַגֵּר | הַגָּר אִתְּכֶם וְאָהַבְתָּ לוֹ כָּמוֹךָ כִּי גֵרִים הֱיִיתֶם בְּאֶרֶץ מִצְרָיִם אֲנִי יְקוָֹק אֱלֹקיכֶם
The stranger who sojourns with you shall be as a native from among you, and you shall love him as yourself; for you were strangers in the land of Egypt. I am the L-rd, your G-d.
There are actually several places in the Pentateuch where this idea is mentioned, e.g.:
תּוֹרָה אַחַת יִהְיֶה לָאֶזְרָח וְלַגֵּר הַגָּר בְּתוֹכְכֶם - One law shall be to him that is native, and unto the sojourner that sojourneth among you.
כְּאֶזְרָח מִכֶּם יִהְיֶה לָכֶם הַגֵּר הַגָּר אִתְּכֶם וְאָהַבְתָּ לוֹ כָּמוֹך כִּי גֵרִים הֱיִיתֶם בְּאֶרֶץ מִצְרָיִם אֲנִי ה' אֱלֹקיכֶם - The stranger that sojourneth with you shall be unto you as the home-born among you, and thou shalt love him as thyself; for ye were strangers in the land of Egypt. I am the L-RD your G-d.
מִשְׁפַּט אֶחָד יִהְיֶה לָכֶם כַּגֵּר כָּאֶזְרָח יִהְיֶה כִּי אֲנִי ה' אֱלֹקיכֶם - "Ye shall have one manner of law, as well for the stranger, as for the home-born; for I am the L-RD your G-d.'
'הַקָּהָל חֻקָּה אַחַת לָכֶם וְלַגֵּר הַגָּר חֻקַּת עוֹלָם לְדֹרֹתֵיכֶם כָּכֶם כַּגֵּר יִהְיֶה לִפְנֵי ה'. תּוֹרָה אַחַת וּמִשְׁפָּט אֶחָד יִהְיֶה לָכֶם וְלַגֵּר הַגָּר אִתְּכֶם - As for the congregation, there shall be one statute both for you, and for the stranger that sojourneth with you, a statute for ever throughout your generations; as ye are, so shall the stranger be before the L-RD.