(A painting of Sarah holding an infant Isaac)
The name Sarah is a Hebrew name and it means Princess. Sarah who was the wife of Abraham and mother of Isaac was once called Sarai, which means quarrelsome, but after her Husband Abraham made his covenant with the lord, the lord asked Sarai to change her name to Sarah (which also means Noblewomen).
Sarah was one of the greatest women in the Bible (during the time of the Patriarchs) and Abraham could not have been the Prophet/Patriarch without her, and Isaac would not have been the Patriarch he was without her. So we can safely say that without Sarah the Torah would never have been bought down as the Hebrews would not have been worthy enough to be responsible for hearing and being accountable to teach/preach and uphold Gods early Mosaic law (which prepared the world for the coming of the Messiah).