I read through Leviticus 12 (short chapter) and this is the closest I could find:

And in the eighth day the flesh of his foreskin shall be circumcised. Leviticus 12:3

Leviticus 12 does command 8th day circumcision, but most of the text refers to a woman's uncleanliness after childbirth.

I think you may have meant Exodus 12:

And the LORD said unto Moses and Aaron, This [is] the ordinance of the Passover: There shall no stranger eat thereof: But every man's servant that is bought for silver, when thou hast circumcised him, then shall he eat thereof. Exodus 12:43-44

He continues:

And when a stranger shall sojourn with thee, and will keep the Passover to the LORD, let all his males be circumcised, and then let him come near and keep it; and he shall be as one that is born in the land: for no uncircumcised person shall eat thereof. Exodus 12:48

A Gentile (stranger) is by definition not "one that is born in the land", unless he is a slave in Israel, that was bought with silver and circumcised by their Israelite master. Once circumcised, that slave may eat of the Passover sacrifice. As Gentiles grafted into Israel, we were not bought by silver or gold. Peter explains:

Forasmuch as ye know that ye were not redeemed with corruptible things, [as] silver and gold, from your vain conversation [received] by tradition from your fathers; But with the precious blood of Christ, as of a lamb without blemish and without spot: 1 Peter 1:18-19

This is Passover language, but not the literal Passover lamb in Jerusalem, but the sacrifice of Yeshua.

Paul talks to Gentiles about the importance of keeping the feast of Unleavened Bread, but does not say Gentiles may EAT the Passover which is slain in Jerusalem according to the commandment. This is consistent with the Torah.

This explains why when Paul was traveling among the Gentiles, he mentions"the days of unleavened" several times (Acts 12:3 and Acts 20:6) but does not mention Passover except in regard to Yeshua being our Passover. He tells the Gentiles in Corinth:

Purge out therefore the old leaven, that ye may be a new lump, as ye are unleavened. For even Christ our Passover is sacrificed for us: Therefore let us keep the feast, not with old leaven, neither with the leaven of malice and wickedness; but with the unleavened [bread] of sincerity and truth. 1 Corinthians 5:7

The Gentiles knew the Torah. They knew that they could not participate in the EATING of the Passover sacrifice, because they were Gentiles (foreigners). But they REMEMBER the Passover by the instructions of Yeshua to "Do this in remembrance of Me". The "Me" here is the Passover Sacrifice. Gentiles may remember the Passover and keep the feast of Unleavened bread. Yeshua is the Passover which the Gentiles must eat, whether circumcised in the flesh or uncircumcised in the flesh.

Then Jesus said unto them, Verily, verily, I say unto you, Except ye eat the flesh of the Son of man, and drink his blood, ye have no life in you. John 6:53

This is for the Gentile to remain in the Royal Law of Love, even while uncircumcised in the flesh. Yeshua is our righteousness, being the Word of God made flesh.

For Moses describeth the righteousness which is of the Law, That the man which doeth those things shall live by them. Romans 10:5

The Pharisaical "sect of the circumcision" believed that NO commandment of the Torah could be kept while uncircumcised in the flesh. Traditionally, the circumcised could not even enter the home of uncircumcised Gentiles.

And when Peter was come up to Jerusalem, they that were of the circumcision contended with him, Saying, Thou went in to men uncircumcised, and didst eat with them. Acts 11:2-3

This is not a Torah issue, since the Torah does not forbid circumcised men to eat with uncircumcised men. This is a tradition.

But the voice answered me again from heaven, What God hath cleansed, [that] call not thou common. Acts 11:9

Likewise, Gentile adult circumcision, outside of the situation described in the Torah, is also a tradition.

Is any man called being circumcised? let him not become uncircumcised. Is any called in uncircumcision? let him not be circumcised. Circumcision is nothing, and uncircumcision is nothing, but the keeping of the commandments of God. 1 Corinthians 7:18-19