The Parable of the Tares has often been cited in support of various degrees of religious toleration. Martin Luther preached a sermon on the parable in which he affirmed that only God can separate false from true believers and noted that killing heretics or unbelievers ends any opportunity they may have for salvation:
"From this observe what raging and furious people we have been these many years, in that we desired to force others to believe; the Turks with the sword, heretics with fire, the Jews with death, and thus outroot the tares by our own power, as if we were the ones who could reign over hearts and spirits, and make them pious and right, which God's Word alone must do. But by murder we separate the people from the Word, so that it cannot possibly work upon them and we bring thus, with one stroke a double murder upon ourselves, as far as it lies in our power, namely, in that we murder the body for time and the soul for eternity, and afterwards say we did God a service by our actions, and wish to merit something special in heaven."
But while men slept, his enemy came and sowed tares among the wheat, and went his way.