Midrash for Sanhedrin 122:24
האי שגגת מעשה דעבודת כוכבים ה"ד אי קסבר בית הכנסת הוא והשתחוה לו הרי לבו לשמים אלא דחזא אנדרטא והשתחוה לו
[liability to a sacrifice] for [unwitting] idol-worship — Rabbi said: It holds good even if his inadvertency was in respect of the action only. But the Sages say, There must have been forgetfulness of the [principal] law itself.<span class="x" onmousemove="('comment',' Lit., 'the thing (in itself)'. This is in reference to Lev. IV, 2f: If soul shall sin through ignorance… If the priest that is anointed do sin … then let him bring for his sin … etc. In Hor. 7b it is deduced that by ignorance in the case of the anointed priest is meant an inadvertence; viz., the action involving a complete forgetfulness of the prohibition on his part, as against an ordinary individual who has to bring an offering even if his inadvertency was only in regard to the action, but not to the prohibition itself. Now the Sages maintain that this applies to all sins, including idolatry. But Rabbi rules that if idolatry be committed inadvertently by the anointed Priest, though without forgetting that it is forbidden, he is still obliged to offer a sacrifice like an ordinary individual. ');"><sup>20</sup></span>