Not "Your Land"

Sefer Ha'Akeidah writes that this is the reason the pasuk says to take bikkurim from “your land that Hashem gave to you." The mitzvah of bikkurim is meant to remind us that the land is not "yours"; rather, it belongs to Hashem and He gives it to us to use for our needs. Therefore, we take the first crops for Him, to display that we accept that everything is really His.

He writes: "The main way of accepting Hashem... is by recognizing that all goodness comes from Him and that our strength and work does not accomplish anything... Anyone who thinks otherwise is guilty of rebelling against Him, which will lead to much badness and punishment. For this reason, we are told that when we enter our land and settle there, we must be careful not to say that we acquired it due to our strengths and talents. We must not forget all the miracles of Hashem that brought us there. Therefore, we must give maaser and other offerings as a constant reminder that all of the land belongs to Hashem's and He only gives it to us as a gift, and that He is the One who grants us success. We are told to give bikkurim 'from your land', meaning from the land that you think is yours but really is not... because all of the land belongs to Hashem."

However, it is common for people to believe that they inherited the land and that it fully belongs to them. Therefore, we are told "to take" (v'lakachta) bikkurim. It does not say "to give" bikkurim, as we are not giving away anything that belongs to us and we are only permitted to enjoy it after we separate a portion for Hashem, as a sign that we accept the fact that it is not “our land".