The Torah in beginning of Parashat Toledot introduces Ribka as "the daughter of Betuel the Aramean, from Padan Aram, the sister of Laban the Aramean." Rashi comments that the Torah refers to Ribka in this fashion in order to praise her for growing to be a righteous woman in spite of her upbringing. She was the daughter of a wicked man and the sister of a wicked man, and the townspeople among whom she lived were wicked, yet she grew to become a saintly Sadeket.
Why did the Torah point specifically to this particular quality of Ribka? Certainly, there are many qualities for which Ribka deserved praise. Why was this specific aspect of her greatness mentioned, and why is it mentioned in this context?
One explanation is that this praise for Ribka serves to introduce the events related in the subsequent verses, which tell of Ribka’s difficult pregnancy. She experienced unusual pain after conceiving with Yaakob and Esav, and the Torah says that "she went to seek out G-d," meaning, she consulted with the great Sages of the time – Shem and Eber – to find the cause of her pains. Ribka had been raised in a society that was deeply entrenched in sorcery and witchcraft. Whenever a crisis or difficult situation presented itself, the people would consult with fortune-tellers and magicians for guidance. But despite growing up with this culture, Ribka knew to consult with Torah Sages for guidance in times of trouble. She had the wisdom to reject the beliefs and practices of her native land and look to the Hachamim for help. The Torah thus praises Ribka in this context for being righteous despite his pagan upbringing, as an introduction to the story of her consultation with Shem and Eber.
There is also an additional explanation. The very next Pasuk tells that Yishak prayed to Hashem for a child "Nochah Ishto" – while facing Ribka. This might mean that Yishak invoked Ribka’s great merit in his prayer. He asked Hashem to grant them a child specifically in the merit of Ribka, who was righteous despite her idolatrous background. Yishak understood that being a pious, G-d-fearing person in a sinful society is a source of great merit, and he sought to invoke this merit as he prayed for a child. And this is why the Torah makes mention of this quality of Ribka in this context – because it was this quality that rendered her worthy of having children. People born and raised in a corrupt, decadent culture can be expected to grow into corrupt, decadent people. It takes a great deal of strength and fortitude to resist this pressure and live a life of piety and virtue when one is surrounded by sin. Therefore, when Yishak turned to G-d in prayer to beg for a child, he pointed to Ribka, to her merit of opposing the culture in which she was raised. The story of Ribka thus shows us the great merit of this achievement, how those who succeed in resisting negative societal influences are deserving of G-d’s blessings and rewards.