Sforno on Deuteronomy 1:19/ספורנו על דברים א׳:י״ט

1ונלך את כל המדבר הגדול והנורא, a way no one had crossed on foot before because of the many snakes and other predators and their size. These are referred to once more in 8,15. Our sages in Sifri 18 have described that the snakes were as large as beams and the scorpions as bows. If G’d had nonetheless chosen to lead them on this route, it had been to shorten the distance they would have to travel so that they could get to their destination before their tendency to quarrel, etc., would result in major sins. Nonetheless, G’d’s efforts in this respect had not proven to be sufficient; they had sinned on numerous occasions at locations Moses recalls by name.