How do we know that Christ's priesthood is better than the Levitical priesthood?

In Hebrews 7, we find that Jesus was made a priest by an oath from God, establishing Him as a high priest forever after the order of Melchizedek. Unlike the Levitical priests, who had to offer sacrifices continually, Christ offered Himself once for all, providing a perfect atonement for sin. This means that while the Levitical system was necessary, it was ultimately inadequate; the law cannot perfect anyone. Christ’s eternal priesthood guarantees our security and draws us near to God, as He ever lives to intercede for us.