Promises

Rabbi Samla’i explained: Why did Moshe yearn to enter the land of Eretz Yisrael?
Did he feel a need to partake of its fruit or to relish in its goodness?!
Rather, this is what Moshe said: “Yisrael have been given numerous mitzvos that can only be observed in Eretz Yisrael. If only I could enter the land so that I will be able to observe all of them”
(Sotah 14a).

What Does Hashem Promise To Those Who Fulfill The Mitzvot Pertaining To The Land?
Children

‘ואם הפרשתם כראוי בנים זכרים אני נותן לך’ (מדרש רבה משפטים ל”א)

“And if you have separated [terumos and ma’aseros] properly, I will give you male children” .

(Midrash RabbahBeshallach 20)

Blessing

מי הוא זה שתפילתו עולה לשמים, והוא מוריד את הגשמים, ובזכותו רוחות טובות מנשבות לגדל העשבים וכו’ זה שמחלק מעשרותיו בחפניו מדרש רבה נשא יב, יא

Who is the person who merits that his prayers go straight up to Heaven, and in whose merit rain falls and good winds blow to enhance the growth of plants? He who separates ma’aseros by the fistful .

(Midrash Rabbah, Naso 12:11)

Wealth

עשירים שבארץ ישראל במה הן זוכין? בשביל שמעשרין, שנאמר ‘עשר תעשר’ (דברים יד, כב),  עשר בשביל שתתעשר (שבת קיט.)

How are the wealthy in Eretz Yisrael worthy of their riches? On account of that they give ma’aser, as it says: עַשֵׂר תְּעַשֵׂר “You shall surely tithe” (Devarim 14:22) – [i.e.] tithe (aser) so that you may become rich (shetisasher).

 (Shabbos 119a)