The Letter to the Galatians is like the Rhône river before Lake Geneva, and the Letter to the Romans is like the Rhône river after Geneva

In fact, the key idea of the Letter to the Romans is already found in the Letter to the Galatians - but as one Swiss exegete nicely says, the Letter to the Galatians is like the Rhône river before Lake Geneva, and the Letter to the Romans is like the Rhône river after Geneva: above a mountain torrent, below a majestic river. The Letter to the Galatians was written in anger in one brilliant sitting, while the Letter to the Romans was written slowly, after dipping the pen repeatedly in the inkwell

E. Carrere, The Kingdom (2014), tr. J, Lambert, 169

Infuriatingly, this is a classic example of Carrere's lack of footnotes. Which Swiss exegete? Was it one of the dodgy ones?