In my understanding, this Scripture is about being patient on the Lord and accepting that in the right time He will work His will for us. After Jesus died for us, these people were still offering sacrifices of animals for their sins which was the law of Moses. They did not rely on the blood of Jesus to wash away their sins. If they put their trust in Jesus, they would receive His promise of salvation. When we accept Jesus, He sends the Holy Spirit to live in our hearts and guide us.