Sahih Muslim Book 27, Hadith 6
He who has to take an oath, he must not take oath but by Allah. The Quraish used to take oath by their fathers. So he (the Holy Prophet) said: Do not take oath by your fathers.
This hadith is narrated on the authority of Ibn Umar through another chain of transmitters.
He who takes an oath in the course of which he says: By Lat (and al-'Uzza), he should say: There is no god but Allah; and that if anyone says to his friend:" Come and I will gamble with you," he should pay sadaqa.