Exodus 32:29

26 and Moses standeth in the gate of the camp, and saith, `Who [is] for Jehovah? -- unto me!` and all the sons of Levi are gathered unto him;

27 and he saith to them, `Thus said Jehovah, God of Israel, Put each his sword by his thigh, pass over and turn back from gate to gate through the camp, and slay each his brother, and each his friend, and each his relation.`

28 And the sons of Levi do according to the word of Moses, and there fall of the people on that day about three thousand men,

29 and Moses saith, `Consecrate your hand to-day to Jehovah, for a man [is] against his son, and against his brother, so as to bring on you to-day a blessing.`

30 And it cometh to pass, on the morrow, that Moses saith unto the people, `Ye -- ye have sinned a great sin, and now I go up unto Jehovah, if so be I atone for your sin.`

31 And Moses turneth back unto Jehovah, and saith, `Oh this people hath sinned a great sin, that they make to themselves a god of gold;

32 and now, if Thou takest away their sin -- and if not -- blot me, I pray thee, out of Thy book which Thou hast written.`