On the authority of Abu Saʿid—may Allah be pleased with him—that the Messenger of Allah, peace and blessings be upon him, said: “You will most certainly follow the ways (sanan) of those who came before you, step for step, so that even if they were to enter a lizard’s hole, you would enter it as well.” They asked, “Messenger of Allah, the Jews and the Christians?” He replied, “Who else?” (1) The two Imams, al-Bukhari and Muslim, relate the report.

sanan: with a fatḥa on the sīn, meaning “path” or “way.”
those who came before you: the nations that preceded you.
ḥadhu (ḥadhwan): in the accusative as a verbal noun, meaning “you will imitate them exactly.”
al-qudha: with ḍamma on the qāf; the singular of qudhat, the feather on an arrow; an arrow has two equal feathers.
so that even if they entered a lizard’s hole: i.e., hypothetically assuming they could fit inside despite its narrowness.
you would enter it: indicating the strength of your imitation of those before you.
They asked, “Messenger of Allah, the Jews and the Christians?”—that is, are these Jews and Christians the ones whose ways we will follow, or do you mean Jews and Christians in general?
He replied, “Who else?”—an interrogative of denial, meaning: who other than them could it possibly be?
akhrajāh: i.e., al-Bukhari and Muslim transmitted it; the wording here is that of Muslim.

Overall meaning of the hadith: The Prophet, peace be upon him, conveys—while implicitly forbidding what the report entails—that his nation will not leave anything the Jews and Christians used to do without adopting it in full; they will omit nothing, even the most insignificant of their practices. This report is further reinforced