The woman's sin is not given the stamp of approval by Jesus. He very clearly tells her not to repeat it. But the others sins, the sins each person has committed at one point or another, the sins we are guilty of multiple times every day, are put into their proper perspective. Just as the sin of adultery disrupts a person's relationship with God, so also every sin disrupts that relationship. Just as the sin of adultery may be worthy of stoning, so also are all our sins worthy of such severe punishment. The difference doesn't lie in the worthiness of the punishment but in our unworthiness to point fingers when we are also guilty of sinning against our Lord. So our proper response to this account of mercy is to show mercy toward others and spend our time instead in repenting of our own offenses and striving to avoid repeating them.