The commandment to conquer the land – what do the first ones rely on?

Read the words of the Ramban himself. He explains everything: The fourth commandment is that we are commanded to inherit the land that God, blessed and exalted, gave to our ancestors Abraham, Isaac, and Jacob, and not to leave it in the hands of others from among the nations or to be a wilderness. And they said to them (Masehi 33 and Ramban there) And you shall inherit the land and settle in it, for I have given you the land to inherit it, and you shall settle the land. And this is repeated in this commandment in other places, as the Lord says (Deuteronomy 12:1), Come and inherit the land that I swore to your ancestors, and I will set it out for them in this commandment, all of it with its borders and its mountains, as He said, and come to the mountain of the Amorites and to all its neighbors in the Arabah, in the mountains and in the lowlands and in the Negev and by the seacoast, etc., so that they may not leave any place of it. And the proof of this commandment is that the Lord said concerning the spies (there): Go up, as the Lord your God has said to you; do not fear or be dismayed. And he said further (Ezekiel 9:14) And when the LORD sent you from the sanctuary of Barnea, saying, Go up and possess the land which I have given you, and when I would not go up, in this passage it is written, And ye rebelled against the mouth of the LORD your God, and believed him not, nor hearkened unto his voice, a commandment which was a commandment, not a promise. And this is what the Sages call it (Sotah 58:46) A war of a commandment. And thus they said in the final part of Sotah (44:2), Rav Yehuda said, The war of Joshua to conquer, the words of all are obligatory, the war of David to gain, the words of all are permission. And the language of my book (Judges 17:14) And you shall inherit it, and you shall dwell therein by the right that you shall inherit it. And do not be mistaken and say that this commandment is the commandment in the war against the seven nations that we were commanded to destroy, that we (the Rabbis of Shofti) should banish them. This is not so. We were commanded to kill those nations in their war with us, and if they wanted to make peace, we would make peace with them and leave them on certain terms, but we would not leave the land in their hands or in the hands of any other nation for a generation or generations. And likewise, if those nations fled from us and went their way, as they (the Rabbis of Shofti) said, “The Gergash turned and went his way, and the Holy One, blessed be He, gave them a good land like this African land of theirs, we were commanded to come into the land and conquer the states and settle our tribes in it. And likewise, after we destroyed the mentioned nations, if our tribes later wanted to leave the land and conquer the land of Shinar or the land of Assyria for themselves, and they were not permitted to leave the places. We were commanded to conquer it and settle it. And from their article Joshua’s war to conquer, you will understand that this commandment is about conquering. And so they said in my book (Sf. Akeb): Every place that your foot will tread on I have given to you, as etc. He told them, “All the place that you will conquer, except for these places, is yours or they have permission to conquer beyond the land until they conquer it.” The Talmud says, “And you will inherit great and mighty nations, and then all the place that is, etc.” And they said, “And if you ask why David dried up the rivers of Aram and Aram became a desert, and there are no mitzvot that are practiced there,” they said, “David did not do it according to the Torah. The Torah said, ‘When the land is conquered, you will be permitted to conquer a foreigner outside the land,’ and he did not do so. Indeed, we were commanded to conquer it in all generations. And I say that the mitzvah that the sages sailed through it, and it is the dwelling place of the Land of Israel, until they said (2 Sam. 5:4, 11:2, 12:5, 13:5, 14:5), that anyone who leaves it and dwells outside the land will be in your eyes as an idolater, as it is said, ‘They have driven me out today from the inheritance of the Lord, saying, “You shall serve other gods, and this is a great sacrifice.” They said in it, “Everything is from this positive mitzvot that we were commanded to inherit the land and dwell in it.” If so, it is a positive mitzvah for generations, binding every individual from it, even during exile, as is known in the Talmud in many places. And the language of my books (see 12:29) is a story told by Rabbi Yehuda ben Betira and Rabbi Matthias ben Harash and Rabbi Hananiah ben Achi, Rabbi Yehoshua and Rabbi Nathan, who were traveling abroad and arrived at Pelatiah and remembered the Land of Israel and raised their eyes and shed tears and tore their clothes and read this scripture and inherited it and lived in it and kept doing it. They said that the Yeshivas of the Land of Israel are equivalent to all the commandments in the Torah: