What are the consequences of saying "It is haram for me from my wife that I shall not enter your room with my foot again," with the intention of suspending the wife's divorce in order to refrain from entering the room, and then entering the room out of necessity or by walking on one's hands?

The preponderant view is that swearing an oath of divorce (tahleef bil-haraam) with the intention of divorce results in divorce upon the breaking of the oath. So, if you enter your sister's room, your wife is divorced, unless you enter forgetfully or under duress. In such a case, there is a difference of opinion regarding the occurrence of divorce, with some verifiers not considering it to occur in this situation.

The duress that is taken into consideration is entering without your own free will, such as being carried or threatened with death or severe beating by someone capable of carrying it out, and not merely the need to enter. So, if you swore not to enter a house and were carried into it and could not resist, then there is no breach of the oath. However, if you were carried by your own command, then you have breached the oath.

If by your oath you intended to abstain from entering specifically with your feet, then you do not break your oath by entering on your hands. However, if you intended to abstain from entering absolutely and did not intend to specify entering with your feet, then the intention accompanying the oath is what matters. Oaths are built upon intention; whenever one intends by their oath something that it can bear, their oath is tied to what they intended. If no intention exists, then it reverts to the cause of the oath and what provoked it.

Your oath is dissolved simply by your entering the room voluntarily and not forgetfully, and divorce occurs. If this divorce does not complete the three divorces, then you may reconcile with your wife before the expiration of her waiting period (iddah). However, if you have previously divorced your wife twice, then if you enter the room, your wife is irrevocably divorced (bainunah kubra).

This is the fatwa according to the majority of scholars. As for the view of Sheikh al-Islam Ibn Taymiyyah, divorce does not occur, but rather you are required to pay an expiation for breaking an oath (kaffarat yamin). Since the issue is subject to scholarly disagreement, it is preferable to present it to a Sharia court or trusted scholars.