How do we know Jesus' power to forgive sins is true?

In Mark 2:10, Jesus, addressing the doubts of the scribes, asserts His authority by stating that the 'Son of Man hath power on earth to forgive sins.' To validate this claim, He performs a miracle by healing a paralyzed man, showcasing His ability to do what is humanly impossible. This dual display of authority both in forgiving sins and performing miracles offers undeniable evidence of His divine nature and power. It reassures believers that He is capable of offering forgiveness to all who come to Him in faith.