How do we know Jesus was without sin?

The sinlessness of Jesus is fundamental to his identity as our Savior. Unlike Adam, who was created without sin but not immutably so, Jesus was born into the world without any sin as stated in Hebrews 7:26, which describes him as 'holy, harmless, undefiled, separate from sinners.' His virgin birth ensured that he did not inherit original sin from Adam, as he was not a son of Adam but rather the son of Mary, thus fulfilling the role of the perfect sacrifice for the sins of humanity. This aspect of his nature is crucial, as Romans 8:3 states that God sent His Son in the likeness of sinful flesh to condemn sin in the flesh, confirming Jesus's unique position in salvation.