John Trapp on Psalms 91:4

Verſ. 4. He ſhall cover thee with his feathers] As the Hen doth her Chickens; Fides eſt quae pullaſtrum, Chriſtum gallinam facit, ut ſub pennis ejus, ſperes; num ſalus in pennis ejus, ſaith Luther: It is Faith which maketh thee the little Chicken, and Chriſt the Hen; that thou maiſt hide, and hope, hover, and cover under his wings; for there is health in his wings.

And under his wings ſhalt thou truſt] For without Faith what uſe is there to us of the Promiſes. Non de ſe debet ſperare Chriſtianus; ſi vule eſſe firmus vapore materno nutriatur, ut pullus gallinaceus, ſaith Austin; Let no man hope for ſafety or ſtrength, but under Chriſts wings graciouſly ſtretcht out over him.