This is clearly not first and foremost a religious image intended as a visual aid to the viewer’s devotional exercises and prayer. Such images - even earlier depictions of the Rest on the Flight into Egypt in which the Virgin and Christ child dominate the landscape and are depicted head-on as in a icon - were intended to stimulate the viewer’s empathy and thereby serve as a devotional aid. This was usually done by including references to Christ’s passion within the picture, often in symbolic form (for example, grapes to signify the blood he would later shed), to assist the viewer in contemplating the Biblical narrative. While this clearly is not the intention here, this picture does incite the viewer’s empathy in a more subtle way through the perilous landscape, and by showing the actual journey itself, rather than a snapshot of the Holy Family resting. Because they are shown moving through the landscape, and because of the way the terrain in the foreground is painted, your eye is encouraged to follow them and their path, thereby involving the viewer in the narrative in another way. You immediately apprehend the danger - apparent impossibility, even - of descending the drop, getting over or through the rocky area and eventually to somewhere safe.
The vicarious journey that your eyes make as they move into the landscape toward the distant horizon invites speculation that the Holy Family’s destination lies somewhere beyond that horizon. Both the depiction of the Holy Family, who seem to be on the edge of a great chasm, and the composition of the landscape invite contemplation of (and meditation on) their journey and, therefore, the narrative of Christ’s life. By this means, it appeals to the viewer’s emotions, stimulates the viewer’s empathy and thus serves as an aid in his or her devotion. The way in which the landscape evokes awe, wonder and silent contemplation - the way it humbles you and forces the Christian viewer to acknowledge God’s great creation and the futility of human endeavours on earth - assists in this process as well.
Of course, this picture could easily have been appreciated for aesthetic reasons alone. And the journey theme would have appealed to viewers in a very different, secular way as well. Because of the compositional devices that encourage your eye to follow various paths into the landscape, the painting could be used as a means of vicarious travel, for armchair travellers who would never get round to making their own, actual journey through the Alps and never have the opportunity to survey such a panorama from so privileged a vantage point. Viewers could travel extensively (and safely!) in their imagination while still - thanks to the skilful painting - experiencing something of the thrill of confronting the awesome beauty of the Alps.