To “abide” under someone’s “shadow” carries two possible meanings, both of which are applicable here. 

First, it could mean to be permanently preempted by another. The one in whose shadow you live always receives the glory, while you remain in obscurity. Is there any better depiction of the truly devoted Christian heart than this, a heart that is continuously seeking God’s glory rather than personal credit? Such a heart will always find itself at home “in the secret place of the most High.”

The other possible meaning is rather obvious. To “abide” under someone’s “shadow” is to be perpetually in their presence and under their protection. The precious promise of divine protection, found in this verse, is not for those who occasionally seek entrance into the Heavenly Holy of Holies or who rush in before the Mercy Seat only when some problem imperils their well-being. Instead, it is only for those who live in constant communion with “the Almighty.” 

According to this verse, it is those who continuously seek God’s glory, not their own, and God’s face, not His favors (Psalm 27:8), who are promised God’s guardianship before life’s fearsome giants and stormy gales.