ROME — Returning to Italy from Morocco Sunday night, Pope Francis said the problem of child sexual abuse, in all its forms, cannot be tackled without understanding the influence of evil.

“The global scourge [of sexual abuse of minors] is great, but to say that this is not understood without the spirit of evil,” he said March 31. “It is a concrete problem. We must solve it concretely, but say that it is the spirit of evil.”

Speaking aboard the papal plane from Rabat after a two-day visit, the Pope said there is a risk of Catholics becoming Donatists and “forgetting the spiritual dimension.” Donatism is a heresy that holds that the validity of the sacraments depends on the perfection of the priests administering them.

To defeat the spirit of evil requires fighting against it, he said. “We too must struggle with the devil, as we must struggle with human things.”

In reference to forgetting the spiritual, Pope Francis said a reason the Vatican halted the United States’ bishops’ proposed measures for sex abuse reform, slated to be presented at their fall general assembly in November 2018, was because he held they lacked a consideration of the spiritual dimension.

“The proposals [of the U.S. bishops] were too much about organization, about methodologies; a bit without meaning to but it had neglected this second spiritual dimension, with the laity, with everyone,” he said.

The U.S. Conference of Bishops was going to consider two proposals: a new code of conduct for bishops and the creation of a lay-led body to investigate bishops accused of misconduct.

“I want to tell you, the Church isn’t a congregationalist church, it’s a Catholic Church where the bishop takes [the abuse issue] into hand as a shepherd, the pope has to take this in hand,” Francis said. “But how does he take it in hand? With disciplinary measures, with prayer, penance, the accusation of one’s self.”

The Pope recalled that he had explained the importance of including the spiritual in the letter he wrote to U.S. bishops before their weeklong retreat in January.

The retreat, held at Mundelein Seminary in Chicago, was proposed by the Pope in October as an opportunity for the U.S. bishops to reflect and pray after a year of abuse and cover up scandals rocked the Church in the U.S. and worldwide.

“I would be grateful if you were to study both things,” in the fight against sex abuse, he said: “the human part and also the part of the spiritual fight.”