The principle of the hierarchy of truths is not novel to Pope Francis. In Evangelii Gaudium today:
36. All revealed truths derive from the same divine source and are to be believed with the same faith, yet some of them are more important for giving direct expression to the heart of the Gospel. In this basic core, what shines forth is the beauty of the saving love of God made manifest in Jesus Christ who died and rose from the dead. In this sense, the Second Vatican Council explained, “in Catholic doctrine there exists an order or a ‘hierarchy’ of truths, since they vary in their relation to the foundation of the Christian faith.”[Unitatis Redintegratio 11] This holds true as much for the dogmas of faith as for the whole corpus of the Church’s teaching, including her moral teaching.
One factor ideally applied here is discernment. I know: you readers are likely getting fatigued with the frequency of that word on this site. But in applying Church teaching to life situations, to where people live, it is needful to diagnose accurately, and to apply directly the Word of Christ to their best effectiveness.
The “heart” of the Gospel, as headlines this section, is the Paschal Mystery: Christ’s death and resurrection. Does this heart come through in our mission in the world?