Philo Judaeus Quod Deterius Potiori Insidiari Soleat 96

But on him who is incapable of receiving repentance on account of the enormity of the pollution which he has incurred by the murder of his brother, namely, on Cain, he lays well-deserved and fitting curses; for in the first place he says to him, "And now, cursed art thou upon the earth:" ¹ showing first of all that he is polluted and accursed, not now for the first time when he has committed the murder, but that he was so before, the moment that he conceived the idea of it, the intention being of equal importance with the perfected action;