He Shall Cover You With His Feathers.

God himself will be their protector those must needs be safe who have him for their keeper, and successful for whom he undertakes: He shall cover thee, shall keep thee secret Psalm 31:20, and so keep thee safe, Psalm 27:5. God protects believers with the greatest tenderness and affection, which is intimated in that, He shall cover thee with his feathers, under his wings, which alludes to the hen gathering her chickens under wings, Matthew 23:37. By natural instinct she not only protects them, but calls them under that protection when she sees them in danger, not only keeps them safe, but cherishes them and keeps them warm. To this the great God is pleased to compare his care of his people, who are helpless as the chickens, and easily made a prey of, but are invited to trust under the shadow of the wings of the divine promise and providence, which is the periphrasis of a proselyte to the true religion, that he has come to trust under the wings of the God of Israel, Ruth 2:12.

With the greatest power and efficacy. Wings and feathers, though spread with the greatest tenderness, are yet weak, and easily broken through, and therefore it is added, His truth shall be thy shield and buckler, a strong defence. God is willing to guard his people as the hen is to guard the chickens, and as able as a man of war in armour. - Matthew Henry