The verse states, ‘[The Torah] is a tree of life to those who cleave to it’. One would expect it to say, ‘to those who support it’, however, the verse is teaching us that the world only exists due to the Torah, as it says, ‘if not for my covenant day and night, I would not have set the rules of heaven and earth’. Even after the world was created, if Torah learning would cease for one minute, the world would cease to exist. So a person who supports Torah should be aware that really the Torah is supporting him, and the impression that we support Torah is only an illusion. We see this also in the Holy Ark that held the tablets of the ten commandments, that athough the kohanim had the privilege to carry it, in truth it carried them when they put their hands on it. When a person financially supports Torah learning, the Torah gives him sustenance and life. Therefore it states, ‘to those who cleave to it’, to teach us that our very existence depends on our cleaving to the Torah.
י״ט באלול 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