Pope Francis on Sunday told teenagers, gathered in St. Peter’s Square for a three-day event related to the pontiff’s jubilee Year of Mercy, that happiness can’t be downloaded like a cellphone app.

Francis used the reference to connect to faithful aged 13-16 who are converging on Rome for a Holy Year weekend for teenagers.

During his homily Sunday in St. Peter’s Square, he told a crowd of 100,000 that “happiness has no price” and is “not an app that you can download on your phones, nor will the latest update bring you freedom and grandeur in love.”

A day earlier, in a video message to the teens’ rally in a Rome stadium, Francis likened being out of contact with God through lack of love to being where there’s no cellphone reception.

After Mass, dozens of white-robed priests surrounded Francis, many snapping selfies with him.

Francis also prayed that a “merciful” God will touch the hearts of those in Syria who have abducted Catholic and Orthodox faithful, including bishops and priests, so that the captives will be released soon.

Francis told tens of thousands of people in St. Peter’s Square where he celebrated Mass Sunday that he was very concerned about those held captive in Syria, which has been ravaged by five years of civil war.

The pope didn’t cite any particular hostage by name. He also appealed for prayers for all persons held kidnapped in the rest of the world.