What covenant did HaSh-m establish with Noach?
Rashi: (a) That the fruit would not rot; and (b) that the Resha'im of that generation would not kill him. 1
Seforno, Ramban (citing Ibn Ezra #1): This refers to the covenant that HaSh-m would make with Noach after the Flood.
Ramban (citing Ibn Ezra #2): That Noach and his family would not die in the Flood.
Ramban: That he would arrive in the Ark together with his family and all the animals, and that they would live there and come out alive.
The commentaries prefer this explanation from the fact that the order of the two phrases, "And I will establish My covenant with you, and you will come to the Ark."
Rashi writes: "From here [we learn] that they were forbidden to have marital relations." Why does Rashi repeat this derivation below (Bereishis 7:7)? Also, why only there does Rashi give a reason
Gur Aryeh (to 7:7): Our verse might be interpreted as forbidding procreation before the Flood, so as not to require a larger Teivah. The later verse adds that even once they entered the Teivah they were forbidden, because the world was in distress.
Why does the Pasuk here mention first the men and then the women, whereas later, when permitting Noach to leave the Ark, HaSh-m told him that he and his wife, his children and their wives, should exit the Ark?
Rashi: As of the beginning of the Flood, marital relations would be prohibited, 1 whereas upon leaving the Ark, they were once again permitted.
רש"י: מכאן שנאסרו בתשמיש המטה: למה נכפלה הדרשה הזו לקמן (ז,ז)? ולמה רק לקמן מוסיף רש"י טעם- מפני שהעולם שרוי בצער?
גור אריה: את מה שכתוב כאן אפשר לפרש שנאסרו בתשמיש עד בואם לתיבה כדי שלא יוליד ויזדקק לתיבה גדולה, ולכן כפל לקמן "ובאת אתה ובניך"- גם אחרי בואם לתיבה נאסרו בתשמיש. ולכן הוסיף שם רש"י שטעם האיסור בגלל שהעולם שרוי בצער.