The children, Perez and Zerah, born to Judah and Tamar were the result of of an illicit union on at least two levels:
- Judah believed she was a prostitute at the time
- The fact that Tamar was Judah's daughter-in-law made the union incestuous.
Judah admitted his mistake and adopted correctly raised the children as his own (what other proper choice did he have??). The fact that these children were both illict, illegitimate and had a foreign mother did not prevent them from being counted among God's people, the Israelites at the time. The appendix below for many more examples.
It appears that, as with the case of Ruth, anyone who wanted to obey the Israelite covenant, could be one of the peoiple of God and that biological decent from Abraham was NOT required - only spiritual descent was necessary as per Gal 6:16 and Rom 9:6 - "For not all who are descended from Israel are Israel."
Despite their poor biological inheritance, Perez and Zerah appear to have embraced the service and loyalty of God as they became the joint patriarch's of the Israel's most powerful tribe and one of few to service to the present.
As further evidence of this, note that Israel's great King David had numerous (biological) foreigners in his ancestory including, Tamar, Rahab, Ruth - there may have been more but this all we have recorded.
The key to resolving the potential theological clash with the requirements of Deut 23:2 about the 10th generation appears to be Ruth dedication/conversion speech recorded in Ruth 1:16, 17 -
But Ruth replied: “Do not urge me to leave you or to turn from
following you. For wherever you go, I will go, and wherever you live,
I will live; your people will be my people, and your God will be my
God. Where you die, I will die, and there I will be buried. May the
LORD punish me, and ever so severely, if anything but death separates
you and me.”
Thus, it appears that anyone was free to convert to the service of the LORD God of Abraham, Isaac and Israel. In the absence of such, it would take to the 10th generation.
APPENDIX - Foreigners who were Israelites?
- When Jacob entered Egypt, his family numbered 75 people (Acts 7:14, Ex 1:5). Some of these were not direct descendants of Abraham such as the wives of the 12 patriarchs, notably Joseph’s own wife. 215 years and four generations later at the exodus, Israel’s army had over 600,000 men, excluding women and children, (Ex 12:37, Num 1:46, etc) suggesting a total population of several million people, requiring many additions. This included a significant mixed multitude (Ex 12:38) showing that Israel obviously consisted of many non-biological Jews had joined. (Note that it is biologically impossible for Israelite numbers to have grown from 75 to several million biologically without many outside additions.)
- Moses married a Midianite (Ex 2:16-21) also known as a Cushite. Miriam and Aaron were severely reprimanded and punished for displaying racism (Num 12:1, 2)
- Caleb, who represented and led the tribe of Judah was a Kennizite (Num 32:12).
- Rahab was a Canaanite (Josh 2:1, 2, Matt 1:5)
- Ruth was Moabite (Ruth 1:4 16, 17, Matt 1:5) – these last two make King David descended from foreigners (Ruth 4:13-16).
- Uriah was a Hittite (2 Sam 11:3)
- King David’s elite personal regiment was Gittite, Philistines (2 Sam 15:18-22, 1 Chron 18:17)
- Isa 56:6, 7 - And the foreigners who join themselves to the LORD to minister to Him, to love the name of the LORD, and to be His servants— all who keep the Sabbath without profaning it and who hold fast to My covenant—I will bring them to My holy mountain and make them joyful in My house of prayer. Their burnt offerings and sacrifices will be accepted on My altar, for My house will be called a house of prayer for all the nations.” See also V3.
- The Rechabites were Kenites (Jer 35:1-19)
- Many other foreigners lived in Israel (1 Chron 22:2, 17, 2 Chron 30:25)
- In Esther’s time “many of the people of the land became Jews” (Esther 8:17, 9:27)
- Even in NT times, many Jewish synagogues were attended by godly gentiles converted to Judaism (Acts 13:16, 26, 16:14, 17:17)
- Many Jewish proselytes came to worship in Jerusalem (John 20:20, Acts 2:9-11)
- Jesus quotes Isa 56:7, “My house shall be a house of prayer for all nations”, Mark 11:17.