They shall bear thee up ... - As if they took hold of thee, and held thee up, when about to fall.
Lest thou dash thy foot ... - Lest you should stumble and fall. They will protect you so that you may walk safely.
Related Commentaries of Psalms 91:12
Psalms 91:12
12 They shall bear thee up in their hands, lest thou dash thy foot against a stone.