This is a saying from 1155 of Saint Bernard of Clairvaux. Its English correspondent is “The road to hell is paved with good intentions“.
It so nicely characterise the latest position of Mr Donald Trummp, the current US President. White House spokesman Sean Spicer says Donald Trump’s immigration ban was issued with very good intentions, wshing getting ahead of threats and putting homeland security first.
In other words, moral certainty can justify the harm done by failing policies and actions.