It was to make atonement for the sins of those seeking Jehovah’s forgiveness. The blood of the bull and the goat was to be spattered toward and before the cover of the ark of the covenant.
فَقَدْ خُصِّصَ ٱلدَّمُ لِقَصْدٍ مُمَيَّزٍ ،‏ أَلَا وَهُوَ ٱلتَّكْفِيرُ عَنِ ٱلْخَطَايَا لِنَيْلِ غُفْرَانِ يَهْوَهَ .‏