- Peninei Halakha
The verse states: "I adjure you, O maidens of Jerusalem, by gazelles or by hinds of the field: Do not wake or rouse love until it please!" (Shir Ha-shirim 2:7). The Sages explain that God administered three oaths: two to Israel – not to ascend to their land forcefully all together (lit. "on a wall") and not to rebel against the nations – and one to the gentiles – not to subjugate the Jews excessively (Ketubot 111a). Afterward, the Gemara adds three other oaths that God administered to the Jews: "That they will not reveal the End of Days, that they will not delay the End, and that they will not reveal the secret to the idolaters." Furthermore, "R. Elazar says: The Holy One, blessed be He, said to Israel, ‘If you fulfill the oath, well and good; but if not, I will allow your flesh [to be devoured] like [that of] the gazelles and the hinds of the field.’"
R. Yitzĥak de Leon, author of Megilat Esther, understands the oaths to mean that "we may not rebel against the nations and conquer Eretz Yisrael by force," and this is what the Sages meant when they stated that we may not ascend "on a wall." Based on this, he concludes that there is no mitzva to settle Eretz Yisrael until the Messiah arrives (gloss on Ramban’s addendum to Sefer Ha-mitzvot, Positive Commandment 4).
However, the rest of the great Rishonim and Aĥaronim maintain that the mitzva of settling Eretz Yisrael is fixed and eternal, as Ramban states and as Shulĥan Arukh (eh 75:3-5), and Pitĥei Teshuva (eh 75:6) assert. Thus, one should not infer from this aggadic statement that the mitzva of settling Eretz Yisrael no longer applies.
Many interpretations have been given for the three oaths. Several of them imply that we must not precipitate the End of Days by ascending to the land by force, without first considering the matter realistically. Indeed, there is reason to fear that, because of the hardships of exile and the protracted period of longing for redemption, people will ascend to Eretz Yisrael impetuously, without any practical means by which to build the land and defend themselves against the nations of the world. This will lead to destruction and crisis instead of the beginning of the redemption. Therefore, God made us swear that we will not attempt to return before carefully calculating our actions. Rather, we should ascend and build the land gradually, in coordination with the nations of the world, or by way of manifest miracles, if we deserve the "I will speed it" form of redemption.
Indeed, the modern return to Zion occurred gradually. The Jewish community in Eretz Yisrael established itself through small steps, while the Zionist Organization simultaneously engaged in diplomatic efforts, until the world recognized the Jewish people’s right to return to their land and build a national home there. Accordingly, after the League of Nations agreed, at the San Remo conference, to return Eretz Yisrael to the Jewish people, R. Meir Simĥa of Dvinsk wrote that "the fear of the oaths has departed."
 The full quote is cited in Ha-tekufa Ha-gedola, p. 175. We will mention a few of the sources. Rashi explains the Gemara’s statement "They shall not go up as a wall" to mean, "Together, with a strong hand." Avnei Nezer, yd 453, states that if the Jews ascend to Eretz Yisrael with the permission of the nations, it is not considered "with a strong hand." R. Yisakhar Shlomo Teichtal concurs in Em Ha-banim Semeiĥa, pp. 226-228 (English edition), adding that when the Jews in exile encounter great suffering, it is a heavenly sign that they must ascend to Eretz Yisrael (see the index there). R. Zvi Yehuda Kook explains this principle briefly in Li-netivot Yisrael, vol. 2, pp. 274-275. The entire comprehensive work of R. M. M. Kasher, Ha-tekufa Ha-gedola, is filled with sources for the mitzva of settling Eretz Yisrael and the beginning of the redemption, as well as explanations of the three oaths; see pp. 175-176, 273ff.
Even if one wants to explain the oaths differently, the rule is that we do not derive halakha from aggadic statements (Avnei Nezer, yd 454). Hence, Rif, Rosh, and all the other early halakhic commentators on Ketubot do not mention the three oaths. On the contrary, they write that there is a mitzva to ascend to Eretz Yisrael. Likewise, Rambam and sa do not mention the oaths in their works. Pnei Yehoshua (on Ketubot 111a) points out that Yoma 9b implies the opposite – that the redemption did not come because the Jews did not ascend as a wall. And since these two aggadic sources contradict each other, we must understand them in some other, non-halakhic way. According to Sefer Hafla’ah (Ketubot, loc. cit.), the "wall" only relates to the immigration to Eretz Yisrael from Babylonia. The Vilna Gaon writes in his commentary to Shir Ha-shirim that the oaths relate to the construction of the Temple, warning us not to be overly eager and build it without divine authorization, given through a prophet. According to R. Tzadok Ha-Kohen of Lublin (Divrei Sofrim §14), even Megilat Esther would agree that there is a mitzva to settle Eretz Yisrael nowadays. For a comprehensive treatment of this issue, see Naĥalat Yaakov by R. Yaakov Zisberg, vol. 2, pp. 715-815.