Without his knowing it, Judah, whose name means "praise", would be the ancestor of Jesus Christ, our Savior and Messiah.
In one account in the Old Testament, we find the grace of fully manifest, in spite of the broken character of this patriarch:
"6And Judah took a wife for Er his firstborn, whose name was Tamar. 7And Er, Judah's firstborn, was wicked in the sight of the LORD; and the LORD slew him. 8And Judah said unto Onan, Go in unto thy brother's wife, and marry her, and raise up seed to thy brother. 9And Onan knew that the seed should not be his; and it came to pass, when he went in unto his brother's wife, that he spilled it on the ground, lest that he should give seed to his brother. 10And the thing which he did displeased the LORD: wherefore he slew him also." (Genesis 38: 6-10)
Because his daughter-in-law still had not conceived a child, and everyone of Judah's sons ended up getting killed because of their wickedness, Judah withheld his next son from lying with Tamar.
Judah's fears were misplaced and selfish, and thus he withheld his son from his daughter-in-line.
When his wife died, he sought comfort in another country. Taking advantage of his departure, Tamar dressed herself as a prostitute, then gave herself over to him in order to conceive a son.
Of course, when Judah found out that Tamar was pregnant, he was ready to have her killed:
"And it came to pass about three months after, that it was told Judah, saying, Tamar thy daughter in law hath played the harlot; and also, behold, she is with child by whoredom. And Judah said, Bring her forth, and let her be burnt." (Genesis 38: 24)
Tamar was ready with proof that he was the father:
" 25When she was brought forth, she sent to her father in law, saying, By the man, whose these are, am I with child: and she said, Discern, I pray thee, whose are these, the signet, and bracelets, and staff. 26And Judah acknowledged them, and said, She hath been more righteous than I; because that I gave her not to Shelah my son. And he knew her again no more." (Genesis 38: 25-26)
Even though she had prostituted herself, Judah had done great wrong in sleeping with a harlot, and withholding her son from his daughter-in-law.
Now, under law, harlotry is wrong:
"6None of you shall approach to any that is near of kin to him, to uncover their nakedness: I am the LORD." (Leviticus 18: 6)
"17There shall be no whore of the daughters of Israel, nor a sodomite of the sons of Israel. 18Thou shalt not bring the hire of a whore, or the price of a dog, into the house of the LORD thy God for any vow: for even both these are abomination unto the LORD thy God." (Deuteronomy 23: 17-18)
Yet Judah, Tamar, and the rest of the Patriarchs were living under a dispensation of faith, of grace:
"1Now the LORD had said unto Abram, Get thee out of thy country, and from thy kindred, and from thy father's house, unto a land that I will shew thee:
2And I will make of thee a great nation, and I will bless thee, and make thy name great; and thou shalt be a blessing:
3And I will bless them that bless thee, and curse him that curseth thee: and in thee shall all families of the earth" (Genesis 12: 1-3)
It's all about faith, not law:
"For the promise, that he should be the heir of the world, was not to Abraham, or to his seed, through the law, but through the righteousness of faith." (Romans 4: 13)
We are blessed today with the righteousness of God because of Jesus!
"For he hath made him to be sin for us, who knew no sin; that we might be made the righteousness of God in him." (2 Corinthians 5: 21)
And Jesus came from the line of Judah, through Tamar:
"2Abraham begat Isaac; and Isaac begat Jacob; and Jacob begat Judas and his brethren; 3And Judas begat Phares and Zara of Thamar; and Phares begat Esrom; and Esrom begat Aram;" (Matthew 1: 2-3)
Tamar is one of four women mentioned in Matthew's genealogy of Jesus!
Once again, we see the grace of God, which surpasses the law, which gave us Jesus, who is grace and truth personified (John 1: 17)