I disagree. When you are absolutely sure that God itself is on your side, then there is no atrocity to big to commit. I feel that religious zeal has led to some of the worst catastrophes in human history. I would put para-religious zeal in that category too, like dogmatic forms of communism.

You can substitute "Truth", "Most Rational Action", or "Reality" in for God in your sentence and still get the same meaning.

People can and will justify almost everything.