וחשב אפודתו אשר עליו כמעשהו ממנו יהיה (תצוה כח:ח)

Chazal says: Hashem doesn’t reckon the thought of committing an averia (sin), except for avodah zara (serving an idol). Hashem does reckon the thought as if one committed the actual sin.  The Medrash says that the אפוד served as a repentance for the sin of avodah zara.  This is alluded to in the pasuk ‘’וחשב אפודתו” – that the מחשבה – even the thought of avodah zara “כמעשהו”  is reckoned by Hashem as if one transgressed.