in weekly Parsha toldot we see that Hashem listened to prayer of Yitchok not Rivka.... Rashi gives us that Hashem listened to prayer that Yiztchok was tzaddik and more rightness family tree ,,, why Hashem listens to prayers of tzaddikim more than others or is this exceptional case?

Shalom, Thank you for your question. You are correct in your reading of Rashi - the Torah tells us that even though both Rivka and Yiztchak were praying, Hashem answered Yitzchak. This leads to the question of why the Torah would not say that Hashem answered Rivkah, or answered them both? Rashi answers that “the prayer of a Tzadik who is the child of a Rasha (evil person) is not comparable to the prayers of a Tzadik the child of a Tzadik”. That is Yizchak was the child of Avraham and Sarah, but Rivkah was the child of Betuel, an evil man. There are several points to note here. Firstly, we learn from here that the prayers of a person can be answered (or not) due to factors beyond their control. Secondly, it does not say that the prayers of a child of evil people are not heard - just that they are not comparable to the prayers of a child of someone who is righteous. Now to your question - is this a general rule? Interestingly, the halacha talks about this in relation to appointing a Chazan in shule. The Sulchan Aruch (Orech Haim 53) does not mention that one should choose a chazan with great lineage. In fact, one of the early Rabbis - the Rosh, 1200’s - ruled that it is better to pick someone who does not have good lineage in order to bring close those who are distant! There is much discussion about this topic (see the Mishna Brurah ibid). But in short, it is clear that a good lineage may only “tip the scales” when all else is equal (as with Yitzchak and Rivkah). But if there are other factors involved - one is themselves a better person, or we desire to help someone out etc - then lineage will not determine who is the better person to pray for us. As to why this concept exists at all - after all, Rivkah isn’t to blame for her family history! - Perhaps we can suggest that a person from a bad family, through no fault of their own, starts out on a lower spiritual status. When they grow to become a Tzadik, they still may be on a lower level than a child born into a family of Tzadikim. Or, perhaps, even though they may both be truly equal, our prayers may invoke our spiritual ancestors. When we pray today we call out in the name of our great lineage, Avraham, Yitzhak, Yaakov etc. So if in that line we have more “power” as it were, our prayers may be more powerful. But if the line is weak, with evil people in it, it may weaken the prayer. At the end of day, each of us should call out to Hashem with all our hearts, knowing that Hashem listens to all our prayers, no matter who we are. We can leave it up to Him to decide how to answer us. Blessings.