The Second Vatican Council sought to defend the truth of the Church with the "medicine of mercy."
There are many different ways to correct errors within the Church, and the Second Vatican Council sought to put the Church back on course with the “medicine of mercy.”
This is how St. John XXIII explained the aims of Vatican II in his opening address on October 11, 1962.
There is no time when the Church has not opposed these errors; she has also often condemned them, and sometimes with the utmost severity. As for the present time, the Bride of Christ prefers to use the medicine of mercy instead of taking up the weapons of rigor; she thinks that today’s needs must be met by exposing more clearly the value of her teaching than by condemning.
Previous councils in the Church would often define truth by condemning errors, but the Second Vatican Council decided to define truth in the positive, rather than the negative.
Recalling the horror of the previous two World Wars, St. John XXIII explained his reasoning.
What matters above all is that they have learned through experience that external violence exerted on others, the power of weapons, political dominance are absolutely not enough to solve the very serious problems that torment them in the best possible way.
Vatican II turned out to be a very different council than previous ones, choosing a more “merciful” look at the world and its problems, seeking to hold-up the truth of the Gospel for all to see, that they may be drawn to Christ through truth, beauty and goodness.