Exodus 20:3

לא יהיה לך THERE SHALL NOT BE UNTO THEE [OTHER GODS] — Why is this said? Does not the preceding verse state: I — and no other — shall be thy God? But since it states immediately after this, “Thou shalt not make unto thee [any graven image etc.]” I might say that I have only a prohibition that one may not make such gods; whence could I know that one may not retain an idol that has already been made? Perhaps there is no such law! Therefore it states here: “there shall not be unto thee” (thou shalt not have other gods) (Mekhilta.) אלהים אחרים OTHER GODS — which are not gods, but others have made them gods over themselves. It would not be correct to explain this to mean “gods other than Me”, for it would be blasphemy of the Most High God to term them gods together with Him (cf. Mekhilta). Another explanation of אלהים אחרים : they are so called because they are other (i. e. strange) to those who worship them; these cry to them but they do not answer them, and it is just as though it (the god) is another (a stranger) to him (to the worshipper), one who has never known him at all (Mekhilta). על פני BEFORE ME — i. e. so long as I exist; and these apparently superfluous words are added in order that you may not say that no one received any command against idolatry except that generation which went forth from Egypt (Mekhilta).

לֹֽ֣א־יִהְיֶ֥͏ֽה־לְךָ֛֩ אֱלֹהִ֥֨ים אֲחֵרִ֖֜ים עַל־פָּנָֽ͏ַ֗י׃

Thou shalt have no other gods beside me.