VATICAN CITY — Caring for migrants and the poor is as holy a pursuit as opposing abortion, Pope Francis declared in a major document issued by the Vatican on Monday.

Pushing back against conservative critics within the church who argue that the 81-year-old pope’s focus on social issues has led him to lose sight of the true doctrine, Francis again cast himself, and the mission of the Roman Catholic Church, in a more progressive light.

“The other harmful ideological error is found in those who find suspect the social engagement of others, seeing it as superficial, worldly, secular, materialist, communist, or populist,’’ Francis wrote in an apostolic exhortation on the subject of holiness issued Monday morning.

“Our defense of the innocent unborn, for example, needs to be clear, firm, and passionate. Equally sacred, however, are the lives of the poor, those already born, the destitute, the abandoned,’’ he said.

The pope’s vision of holiness explicitly highlights migrants, whose plight he has sought to elevate to global attention perhaps more than any other issue.

“We often hear it said that, with respect to relativism and the flaws of our present world, the situation of migrants, for example, is a lesser issue,’’ he said. “Some Catholics consider it a secondary issue compared to the ‘grave’ bioethical questions.

“That a politician looking for votes might say such a thing is understandable, but not a Christian,’’ he continued, adding that welcoming the stranger at the door was fundamental to the faith. “This is not a notion invented by some pope, or a momentary fad.’’

He stressed that people who show holiness in practical ways are more pleasing to God than religious elites who insist on perfect adherence to doctrine.

The pope’s 103-page document — an apostolic exhortation titled “Gaudete et Exsultate,’’ or “Rejoice and Be Glad’’ — is less authoritative than a papal encyclical but is nevertheless an important teaching pronouncement.

At its outset, Francis says his aim is to restate the need for holiness “in a practical way for our own time.’’ Elsewhere in the document, he says, “Seeing and acting with mercy: That is holiness.’’

That statement is a distilled expression of Francis’ vision of the church, which is consistent with a view articulated by Cardinal Joseph L. Bernardin, the archbishop of Chicago who died in 1996, and who called for a “consistent ethic of life’’ that wove issues of life and social justice into a “seamless garment.’’

The pope is reminding his church to “expand our view,’’ said Archbishop Angelo De Donatis, the vicar general of Rome.

Throughout the document, Francis urges followers to be less consumed with showy demonstrations of faith and piousness than with patiently and lovingly raising children, working hard to support families, and representing what he called “the middle class of holiness.’’

“In their daily perseverance, I see the holiness of the Church militant,’’ Francis wrote, using a phrase that has been appropriated by archconservatives critical of his papacy. The pope’s allies have described the fringe Catholic website Church Militant as openly in favor of political “ultraconservatism.’’

But a majority of the document is a rumination on what constitutes an effective and true practice of holiness.

While he says “ the silence of prolonged prayer’’ is critical, Francis adds that holiness at times requires the faithful to be loud and active and says it “is not healthy’’ to seek prayer while disdaining service.

He cautions against a cold reason untethered from spirituality and warns against an overemphasis on the power of human will alone, “as if it were something pure, perfect, all-powerful, to which grace is then added.’’

In a section of the document titled “Signs of Holiness in Today’s World,’’ the pope explicitly laments a modern culture that includes “the self-content bred by consumerism; individualism; and all those forms of ersatz spirituality — having nothing to do with God — that dominate the current religious marketplace.’’

The pope, like others, is also worried social networks such as Facebook feed into the hedonism and consumerism that “can prove our downfall’’ and are, in short, a waste of time.

“When we allow ourselves to be caught up in superficial information, instant communication, and virtual reality, we can waste precious time,’’ he says.