Moreover the perfect soul turns away from matter, shuns and rejects everything that is excessive or inconstant or wicked, and neither sees nor approaches this earthly defilement and corruption. It is attentive to things divine but shuns earthly matter. But its flight is not to depart from the earth but to remain on earth, to hold to justice and temperance, to renounce the vices in material goods, not their use. Holy David fled from the face of Saul, not indeed to depart from the earth but to turn away from the contagion of a cruel, disobedient and treacherous man. He fled, cleaving to God, just as he himself said, "My soul has stuck fast to you."
Source: On Isaac and the Soul, 3.6