תּוֹרָ֥ה אַחַ֛ת וּמִשְׁפָּ֥ט אֶחָ֖ד יִהְיֶ֣ה לָכֶ֑ם וְלַגֵּ֖ר הַגָּ֥ר אִתְּכֶֽם׃ (פ)
你們和寄居在你們中間的外人，都要遵守同一律法、同一典章。
Mishneh Torah, Forbidden Intercourse
A convert who was circumcised and has not immersed, or has immersed and not circumcised is not a convert until he is circumcised and immersed. And it is necessary to immerse before three (men). And since the matter requires a Beit Din (counsel) - no immersion is done on the Sabbath, nor Yom Tov (holiday) nor at night. And if he was immersed, he is a convert.