A Rosh Yeshiva of a Yeshiva for weaker students posed a question: “My Yeshiva is going through a rough patch currently. What is the best manner in which to strengthen the Torah learning in his Yeshiva? Is it preferable to tell them that the Gedolim are calling for strengthening of Torah learning during this difficult time for Klal Yisroel (which it was) and to give them words of Mussar? Or is it better to encourage them and give them monetary prizes and such things in order to pick up the learning?
Rav Chaim zatzal responded that the Rosh Yeshiva should try the first method and if it works – that would be great. If not, then he could award prizes – when there is no choice, there is no choice.”
This author believes that it seems Rav Chaim zatzal’s motivation was that one should ideally fulfil the Mishna in Avos 1:3 that one should, ideally, not serve the Master for the purpose of receing reward – but one should do it lishma. These bochurim were already somewhat older and it would be ideal to study with purer motivations – but it is not worthwhile to sacrifice the learning on account of this.