The Scofield Bible Commentary, by Cyrus Ingerson Scofield, [1917], at sacred-texts.com
A Song of degrees
Literally, "of ascents." Perhaps chanted by the people as they went up to Jerusalem to the feasts. See, for example (Psa 112:1); (Psa 112:2).
feared
(See Scofield) - (Psa 19:9).
redemption
(See Scofield) - (Isa 59:20).
(See Scofield) - (Exo 14:30).