And Yitzchok prayed intently to Hashem opposite his wife because she was barren and the Lord accepted his prayer, and Rivka his wife conceived. (25:21)
Rashi explains the words: opposite his wife. Yitzchok was standing in this corner and praying, and Rivka was standing in that corner and praying. Many commentaries ask according to Rashi, Why does the Torah have to state the word opposite his wife? What is the difference where they were standing as long that they both prayed. It could have been suffice to simply state “And Yitzchok prayed intently to Hashem”? Another difficulty asks the Sefer Orach Lechaim, -Harav Avraham Chaim Of Zlotchuv a Talmid of the Magid of Mezritch-: The Torah states because she was barren. This implies that Yitzchok was fertile. This is difficult as the Gemarra Yevanmos 64a says: Rav Nachman said to him: Yitzchok knew that he was infertile, and therefore there was no reason for him to marry another woman, as Rivka was not the cause of their infertility. The Gemarra continues: Rabbi Yitzchak said: For what reason were our forefathers initially infertile? Because the Holy One, Blessed be He, desires the prayers of the righteous, and He therefore wanted them to pray for children. The Gemara asks: If so, why does the verse continue: 'And the Lord let Himself be entreated of him'? The verse should say: 'And the Lord let Himself be entreated of them'?
The Orach Lechaim answers that Yitzchok was born infertile but as the Ohr Hachaim states Bereishis 18:10 on the Posuk "I will certainly return." The reason the angel repeated the words and added the word may be better understood on the basis of a tradition that when Yitzchok was born he was sterile. It was only after agreeing to be the sacrifice at the Akeidah that he was cured of that defect. The angel hinted that he would have to return twice at a time when he would "give life," in order that Sarah's son would be a true son, able to reproduce, as Avraham's input, become dominant within Yitzchok.
Continues the Orach Lechaim that Yitzchok recieved a part of the Neshama from Avraham which enabled him to have children. Hence, the words of the Posuk because she was barren, stand true. Therefore, each stood opposite each other and prayed. Rivka prayed for a child as she was barren, and Yitzchok prayed that the child should be an elevated Neshama.
There is another insight to the words Opposite his wife. There is a Midrash that interprets the word for her benefit. This is puzzling! The Sefer Bais Uri from Hagaon Rav Uri Helddenstein Rav in Lisa, answer a beautiful insight: Yitzchok was able to have children, and since Rivka was barren, he faced the choice of marrying another wife to bear children. Yet, Yitzchok knew the value of Rivka, and wanted dearly that she bring him children. Therefore, his prayers were for Rivka for her benefit, that she should be the mother of Klal Yisrael, and not have to marry another wife.
We see in last weeks Parsha that they blessed Rivka and said to her, "Our sister, may you become thousands of myriads, and may your seed inherit the cities of their enemies." Yitzchok heard this blessing from Eliezer, and it was clear to him that Rivka would have children, therefore, he prayed for her.
