Read Hebrews 7:28 Using Other Translations
For the law maketh men high priests which have infirmity; but the word of the oath, which was since the law, maketh the Son, who is consecrated for evermore.
For the law appoints men in their weakness as high priests, but the word of the oath, which came later than the law, appoints a Son who has been made perfect forever.
The law appointed high priests who were limited by human weakness. But after the law was given, God appointed his Son with an oath, and his Son has been made the perfect High Priest forever.