One who says to his fellow, "Konam if I derive any benefit whatsoever from you, if you do not come and collect for your child a kor of wheat and two jugs of wine" - and an occasion of mourning, of a drinking-session, or there were rains, then it is permitted.
"And, if not, he is prohibited until he will find absolution for his view through the ruling of a sage," the words of Rabbi Meir.
And the Sages say, "Also: this one can annul his vow without consultation with a sage."
He may say to him, "Did you not speak only to do me honor? But this is what I deem to be honorable."
And, similarly, one who says to his fellow, "Konam if you derive benefit from me, if you do not come and give my son a kor of wheat and two jugs of wine."