Rabbi Avraham Lichtenstein was an eighteenth-century rabbi of Prassnysz, in the region of Plotzk, Poland, and author of Kanfei Nesharim. In his commentary Migdenos Avraham on Shir Hashirim 8:4, he says regarding the oaths:
Heaven forbid for Israel in exile to make any effort with a strong hand, whether through the gentile kings and ministers, or to go up as a wall, all together, each one strengthening the other, saying, 'Let us go to Jerusalem with a strong hand and build the Temple,' or 'Let us pay off the king of Turkey until he sells us all the state of Eretz Yisroel to be ours like it was in ancient times, and we will build the Temple and offer sacrifices.' Heaven forbid for us to do this! We will wait until Hashem pours out His kindness from above and sends our redemption through his moshiach, with permission from the King Who sits on high.
He quotes a story in the Gemara (Taanis 29a): When the Temple was burning, the young kohanim went up onto the roof of the sanctuary with the keys to the sanctuary in their hands. They said, "Master of the World! Since we did not merit to be trusted custodians, we are handing over the keys to You!" They threw the keys upwards, and a hand came out of heaven and accepted them. Then the young kohanim leapt into the flames.
The Migdenos Avraham explains:
Imagine a person who wants to enter a house, but the house is locked. It appears that the house is ownerless. He wants to break down the door, but we tell him, "Fool! Stop!" The house does have an owner, the keys are in his hand, and you want to enter by force? You will be considered a burglar! Wait till the owner comes and gives you the keys, and then open the door. Here too, since Hashem accepted the keys, how could it occur to us to go up by force without receiving permission from Hashem? We must wait until the Owner of the key comes and gives us the key, and then we will go to Zion with song.
At the same time, Hashem warned the nations of the world not to make the exile too difficult for Israel. This is the meaning of the verses in Shir Hashirim (2:6-7 and 8:3-4) from which the oaths are derived. Israel says to Hashem, "Let His left hand be under my head (i.e. prophecy), and let His right hand embrace me." Hashem replies, "Look what I have already given you during this exile, and see My great love for you. I have adjured the daughters of Jerusalem – the nations – not to afflict you. So why do you pray so persistently for the return of My love and prophecy – better to wait until the proper time, when it is desired."
The Migdenos Avraham mentions that his teachers used the story of the hand accepting the keys to explain the meaning of the words we say in Musaf of Yom Tov: "And we cannot go up and appear and prostrate ourselves before You, in the great and holy house upon which Your name was called, because of the hand that was stretched out upon Your Temple." The words "we cannot" really mean "we are not allowed to" - see the Targum and Rashi on Devarim 12:17. Even though we might be able to force our way in by petitioning the king and his ministers (he uses the words "yad chazakah" - the same words used by Rashi on Kesubos - which shows that he understood Rashi to be in agreement with him), we are not allowed to do so, because of the hand that was stretched out over the Temple to accept the keys from us.
In his commentary on the oath in Shir Hashirim 8:4, he connects the oath with the next verse (v. 5): "Who is this who ascends from the wilderness, overcoming her Beloved? Under the apple tree I woke you, there your mother injured you..." Model your behavior after those early days in the wilderness, when you traveled only when Hashem commanded you to do so. And when, after the sin of the spies, Hashem commanded you not to conquer the land, and you tried to overcome your Beloved and fought anyway, you were injured! So you see that without Hashem's permission, there is no wisdom and no counsel.