The imprint of an Aveira gets on Hashem when one attaches to Him:
When one sins and then Davens to Hashem, attaching to Him through prayer, the imprint of the Aveira Kevayachol gets onto Hashem. This is similar to a dirty stamp which is placed onto wax, in which case the dirt also cleaves to the wax. This sin causes dirt and blemish above. This is an additional motivation to abstain from sin, in order not to damage one’s connection with Hashem.
 Or Torah [Maggid] Vayikra 107