Numbers 9:7

and those men said unto him, We are unclean by reason of the dead body of a man: wherefore are we kept back, that we may not offer the oblation of Jehovah in its appointed season among the children of Israel?

Exodus 12:27

that ye shall say, It is the sacrifice of Jehovah's passover, who passed over the houses of the children of Israel in Egypt, when he smote the Egyptians, and delivered our houses. And the people bowed the head and worshipped.

Numbers 9:2

Moreover let the children of Israel keep the passover in its appointed season.

Deuteronomy 16:2

And thou shalt sacrifice the passover unto Jehovah thy God, of the flock and the herd, in the place which Jehovah shall choose, to cause his name to dwell there.

2 Chronicles 30:17-19

For there were many in the assembly that had not sanctified themselves: therefore the Levites had the charge of killing the passovers for every one that was not clean, to sanctify them unto Jehovah.

1 Corinthians 5:7-8

Purge out the old leaven, that ye may be a new lump, even as ye are unleavened. For our passover also hath been sacrificed, even Christ:

Treasury of Scripture Knowledge

Summary

And those men said unto him, We are defiled by the dead body of a man: wherefore are we kept back, that we may not offer an offering of the LORD in his appointed season among the children of Israel?

General references

Bible References

We may not offer

Numbers 9:2
Moreover let the children of Israel keep the passover in its appointed season.
Exodus 12:27
that ye shall say, It is the sacrifice of Jehovah's passover, who passed over the houses of the children of Israel in Egypt, when he smote the Egyptians, and delivered our houses. And the people bowed the head and worshipped.
Deuteronomy 16:2
And thou shalt sacrifice the passover unto Jehovah thy God, of the flock and the herd, in the place which Jehovah shall choose, to cause his name to dwell there.
2 Chronicles 30:17
For there were many in the assembly that had not sanctified themselves: therefore the Levites had the charge of killing the passovers for every one that was not clean, to sanctify them unto Jehovah.
1 Corinthians 5:7
Purge out the old leaven, that ye may be a new lump, even as ye are unleavened. For our passover also hath been sacrificed, even Christ:

General references

Leviticus 23:5
In the first month, on the fourteenth day of the month at even, is Jehovah's passover.
Haggai 2:13
Then said Haggai, If one that is unclean by reason of a dead body touch any of these, shall it be unclean? And the priests answered and said, It shall be unclean.

American Standard Version Public Domain