The Kossover Rebbe quoted the oath against forcing the end (yidchaku) and applied it to Zionism. Rashi says it means that we must not pray too much; how much more is it forbidden to try to end exile through political means.
According to the other version of the text, that they should not delay the end (yerachaku), we also have a proof against Zionism. Rashi says it means delaying the end through our sins. If sins delay the end, then only teshuva can hasten the end, not political maneuvering.
The Kossover Rebbe says that the reason for the oaths is that every Jew must accept upon himself the yoke of exile lovingly, until the time of the redemption arrives. The exile is of great importance, because it atones for the sin of Adam eating from the Tree of Knowledge. Furthermore, exile was chosen by Avraham our father at the Covenant Between the Parts to spare us from Gehinom. We must not try to force the hour, for in so doing we will really just be delaying the redemption, since G-d will in any case make us return to exile to serve the remainder of our term.
With this in mind, we can explain the two versions of the text in Kesubos 111a as being identical in meaning. According to one version, G-d adjured the Jewish people not to force (yidchaku) the end of exile. According to the other version, the oath was not to delay (yerachaku) the end of exile. Seemingly these two version are opposites, but according to the above, the oath forbids pushing for the end, since by so doing we will really be delaying the end.
Therefore we must be wise and scrutinize any movement that superficially seems to be working to bring the redemption nearer, lest it actually be delaying the redemption.
If we understand the atonement we are getting through exile, wrote the Kossover Rebbe, we can feel its sweetness and accept it lovingly. (Leket Ani)
The Kossover Rebbe brings further proof against Zionism from the Gemara in Sanhedrin 97a: “Whenever Rabbi Zeira saw the rabbis occupied with the subject of moshiach, he said to them, ‘I beg of you, do not delay him.’ For three things come only when our mind is diverted from them, and one of them is moshiach.” From the words of the Gemara, it does not sound like the rabbis were praying for moshiach; it sounds like they were actively seeking ways to accelerate his coming. And Rabbi Zeira told them that this sort of activity actually delays his coming. As Shlomo Hamelech said, “If Hashem does not build a house, its builders toil in vain” (Tehillim 127:1). Not through might and strength will we return to our land, and not through political skill will our kingdom be restored to us. It will happen only when Hashem bestows upon us His spirit of favor from above, and a voice proclaims to us, “Long enough you have dwelt in the valley of weeping! Return, children, to the land of your ancestors!” (Leket Ani, Purim)