As explained above, since we are obligated to know the whole Talmud, one should learn at least the whole RI”F with Rashi. The evil inclination will probably entice a person not to do this saying that this is just an easy way out, and since learning it with other commentaries is too hard, there is no point trying. Of this the verse speaks saying, ‘If you seek it like silver and search it like a treasure then you will understand fear of Hashem and will find knowledge of G-d’. If a person has a small store with which he ekes out a living, would he close it because he can’t get rich from it? Surely he would do whatever he can to survive at least. Similarly a person should not forsake his learning because he will not become rich in Torah, but should do whatever he can to maximize his learning.
ו׳ בכסלו ה׳תשפ״א
"והאמת בלתי שום ספק כלל, שאם היה העולם כולו מקצה עד קצהו פנוי חס ושלום אף רגע אחד ממש מהעסק והתבוננות שלנו בתורה, כרגע היו נחרבים כל העולמות, עליונים ותחתונים, והיו לאפס ותוהו חס ושלום". (נפש החיים) 1