With World Day of the Sick coming up next month, Pope Francis recently tweeted about the importance of caring for those who are ailing.

“It is not only what functions well or those who are productive that matter,” he said in a message the Vatican reported.

“Sick people are at the center of God’s people, and the Church advances together with them as a sign of a humanity in which everyone is precious and no one should be discarded or left behind,” he added in a tweet.

World Day of the Sick is observed on Feb. 11 and has been around for about three decades. Pope John Paul II created the celebration in 1992 as a way to encourage believers to pray for those suffering from illnesses, as well as their caretakers. Around that time, Pope John Paul II had been diagnosed with Parkinson's disease, National Today reports.

It was purposefully decided that World Day of the Sick would be celebrated the same day as the Feast of Our Lady of Lourdes, according to the Catholic Health Association of BC. That feast day is tied to something that happened on Feb. 11, 1858. At that time, a young girl named Bernadette Soubirous said she had seen apparitions of the Virgin Mary around Lourdes, France. Many pilgrims and visitors have said they experienced healing at the Sanctuary of Our Lady of Lourdes in the ensuing years, and the Catholic Church declared Bernadette a saint a few years later.

"When we go on a journey with others, it is not unusual for someone to feel sick, to have to stop because of fatigue or of some mishap along the way,” Pope Francis said in his message. “It is precisely in such moments that we see how we are walking together: whether we are truly companions on the journey, or merely individuals on the same path, looking after our own interests and leaving others to ‘make do.’

He called on people to turn their thoughts to the Shrine of Lourdes over the next few weeks as Feb. 11 approaches.

“I invite all of us to reflect on the fact that it is especially through the experience of vulnerability and illness that we can learn to walk together according to the style of God, which is closeness, compassion, and tenderness,” the pope continued.