Did Pope Francis say that the Gospel is radical? I vaguely remember a quote by Pope Francis, in the context of mercy and his apostolic exhortation Amoris Laetitia, which goes something like "The teaching of the Gospel itself is quite radical", using "radical" in a good way.  The basic meaning of the  quote was somethng like, Pope Francis doesn't need to break new ground in placing a greater emphasis on God's mercy and forgiveness, because the Gospel's teaching on this is already quite earth-shattering if we just listen to it.

Can someone help me identify this quote?  I distinctly remember that the words "Gospel" and "radical" occur in the quote.

I can't seem to find it in Amoris Laetitia, but it's possible that it's from some interview he gave about it, or it's from another document authored by him.
I can't see anything quite like this in the context of Amoris Laetitia, but the pope has used the words together a few times. According to the English-language version of the Vatican Radio website, he preached a homily from his residence in Santa Marta on 23 September 2014 in which he spoke about "the Gospel's call to radical simplicity in life and action". Similarly, in a homily preached for the 6th Asian Youth Day in Korea on 16 August 2014 (PDF), he spoke about "the radical demands of the Gospel". I can't find much else using precisely those words in documents published by the Pope, and nothing about interviews in which he used those words (though that is a more difficult search, especially with off-the-cuff remarks).

Francis was not the first to use "radical" in speaking about the Gospel, though; Pope St John Paul II mentioned the "radicalism of the Gospel" in his 1992 apostolic exhortation Pastores Dabo Vobis, and Pope Benedict XVI spoke of the "radical call of the Gospel" in an address to the bishops of Bangladesh during their ad limina visit in 2008.