(Yerushalmi Halachah 2 Daf 23a)
[דף כג עמוד א] רבי יוחנן מתיב והבאתי אתכם אל (ארץ אבותיכם)[הארץ אשר נשאתי את ידי וגו' ונתתי אותה לכם מורשה] אם מתנה למה ירושה ואם ירושה למה מתנה. אלא מאחר שנתנה להן לשום מתנה חזר ונתנה להן לשום ירושה.
Question (R. Yochanan): The pasuk states (Shemos 6:8), "I will bring you to the land about which I raised My hand...and I will give it to you as a heritage'' - if it is a gift, why say it is a heritage and if it is a heritage, why say that it is a gift? Rather, after Hash-m gave it as a gift, He then took it back and gave it as a heritage. (Note: This entry follows the text of the Kaftor Veferach and others, that R. Yochanan is asking an independent question, unrelated to any previous statement.)
א''ר הושעיה כל מקום שנאמר מורשה לשון דיהא
R. Hoshiyah: Wherever a verse uses the word 'morasha' - an inheritance; its root is from the word 'diha' meaning dull, as although it is in inheritance, it is not fully an inheritance, such as the inheritance of the Land of Israel that was supposed to fall to those that left Egypt and ultimately, it fell to their children.
[דף כו עמוד א (עוז והדר)] התיבון והכתיב מורשה קהלת יעקב
Question: Doesn't it say (Devarim 33, 4), "(The Torah was commanded to us by Moshe), as an inheritance to the assembly of Yaakov'' - and the Torah is a full inheritance?
אמר לית דיהא סוגין מיניה. מן דו לעי היא משכח כולה
Answer (R. Hoshiyah): The inheritance of the Torah is the dullest, because (Torah knowledge) is not something that is inherited from one's parents. Rather, one finds the Torah's true meaning through toil and struggle.