For many of us, we understand peace to be the absence of conflict. We talk about peace in the home or in the world or giving peace a chance. But the Hebraic understanding of shalom is far more than just the absence of conflict or strife.
Shalom is the presence of the goodness of God. It's the presence of wholeness, completeness.
So when Jesus tells the woman to go in peace, he is placing the blessing of God on all of her. Not just her physical body. He is blessing her with God's presence on her entire being. And this is because for Jesus, salvation is holistic in nature. For Jesus, being saved or reconciled to God involves far more than just the saving of your physical body or your soul - it involves all of you.
From Velvet Elvis (p.107)