She was brought to Him by the complacent Pharisees (John 8:3). In answer to the question of whether or not they should stone her (vv. 4-5) Jesus told them that the one without sin should be the first to throw a stone (v.7). This way He reminded them that they were also sinful. One by one everyone left (v. 9).
When the temple courts were empty but for the two of them, Jesus did not condemn the woman (v.11). Though He was sinless and could throw the first stone He chose to forgive, which He indeed had the power to do (Luke 5:24).
Though God is just (Isaiah 5:16) and does not tolerate sin (Isaiah 59:2), He is also compassionate (Psalm 145:8-9) and merciful (Micah 7:18). Jesus did not come into the world to condemn it, but to save it (John 3:17) and "to seek and to save the lost” (Luke 19:10). He admonished the woman “Go now and leave your life of sin” (v.11). Not only did He forgive, but He also called her to a new life. The Bible does not say what she did afterwards, but most likely this was a watershed in her life after which she gave up her sin.
Jesus had mercy on the woman.
How awesome our God is! He deserves our praise!!!