Is my saying to someone, "By divorce, I will not do such and such until they do such and such"—even though I did not originally swear by divorce—considered the creation of an oath or merely a false statement?

This is a false statement that does not result in divorce. The preponderant opinion is that whoever falsely claims to have sworn by divorce does not become one who has sworn, and divorce does not occur due to his action regarding what he claimed he swore upon. It is stated in Al-Mughni by Ibn Qudamah: "If he said: 'I swore by divorce,' or 'I am bound by an oath of divorce,' and he had not sworn, nothing is incumbent upon him between him and Allah the Almighty."