Vaiera - Presents and Inheritance

I will bring you to the land, concerning which I raised My hand to give to Abraham, to Isaac, and to Jacob, and I will give it to you as a heritage; I am the L-rd

 וְהֵבֵאתִי אֶתְכֶם אֶל הָאָרֶץ אֲשֶׁר נָשָׂאתִי אֶת יָדִי לָתֵת אֹתָהּ לְאַבְרָהָם לְיִצְחָק וּלְיַעֲקֹב וְנָתַתִּי אֹתָהּ לָכֶם מוֹרָשָׁה אֲנִי ה' -ה

Shmot 6:8

The Or HaChaim HaKadosh raises a problem with this verse. This verse encompasses a divine promise to Am Yisrael to bring them into the Land of Israel. The verses preceding it also are promises to Am Yisrael, comprising: I will take you out, I will save you, I will redeem you,  I will take you. The problem is that Hashem didn't bring these people out of Egypt and then into Eretz Yisrael, most of them died in the desert. Furthermore these verses are introduced by the phrase "Therefore, say to the children of Israel (לָכֵן אֱמֹר לִבְנֵי יִשְׂרָאֵל) (Shmot 6:6)", which Rashi says  "Therefore (לכן)" means "according to that oath", implying that all of these promises are in a framework of a divine oath.

So, asks the Or HaChaim, how can Hashem make such a promise, a divine oath when it is known that this is not carried out?

A Conditional Promise
Explains the Or HaChaim, the verse that immediately precedes this verse makes all the difference.

and you will know that I am the L-rd your G-d

 וִידַעְתֶּם כִּי אֲנִי ה' קלקיכם

Shmot 6:7

All the other promises in this passage, comprising the famous 4 descriptions of redemption, come before this point.  This statement, "you will know" changes the verse that follows, "I will bring you to the land", into a a conditional promise. The promise to bring Am Yisrael into the land is dependent upon Am Yisrael recognizing and knowing Hashem, which they demonstrated their lack thereof and thus the people leaving Egypt did not reach the land.

Presents and Inheritance
The Slonimer Rebbe in Netivot Shalom focuses on the end of the verse.

I will give it to you as a heritage

 וְנָתַתִּי אֹתָהּ לָכֶם מוֹרָשָׁה

The Rebbe explains that these terms embody two concepts: giving a present and receiving an inheritance. Receiving an inheritance is relatively easy and virtually anyone can receive an inheritance regardless of their stature, intelligence, or accomplishments.

A gift (מתנה) is by nature on a higher level than an inheritance (ירושה).   Each possesses characteristics that the other lacks. Central to an inheritance is that it is not dependent on the nature of the inheritor. Even a simple son can receive the estate of a wealthy, successful father by way of inheritance. While a gift is extended to someone suitable of receiving such a gift, or has earned this by their actions.

• Serving Hashem: This is also reflected in our service to Hashem. One can serve Hashem by adhering to the halachah and keep Shabbat to the letter, but didn't go the extra step to take real enjoyment out of Shabbat. The reward in the world to come will be less, when one doesn't try and push to strive for the extra 'oneg' in the mitzvot in this world. So when one doesn't strive for the extra oneg of Shabbat, then they are just left with fundamental aspect of Shabbat, the inheritance. While the one who strives to get oneg out of Shabbat will be rewarded with the present in the World to Come. 
• Learning Torah: Likewise learning Torah reflects these aspects as well. When Torah is learned at a basic level, without sweat and investment, then one doesn't feel the  true pleasure of Torah learning, and Torah learning remains at the level of inheritance. Yet when one persists and struggles with even difficult Torah learning, then he will feel the true pleasure in learning.
• Eretz Yisrael: One can live and exist in Eretz Yisrael, taking it as their inheritance. However when one endeavors to connect with the true holiness embodied in Eretz Yisrael, then one can appreciate this land as a divine gift.

Inheritance and a Conditional Promise

I believe that the Rebbe's observations fit right into the conclusions made by the Or HaChaim. The difference between a present and an inheritance is like the conditional promise. Something like the Land of Israel can be promised, but depending on our own actions only then will we see how that promise will be realized. It can be a grand gift given immediately, or one only fulfilled after wandering the desert for forty years. It comes down to our actions and how much true enthusiasm we apply.