In this text we have
I. A charge given "Fear not." A righteous, godly fear the believer may have; but the cowardice of the world, which is loud to boast, and slow to act, and quick to doubt which is prone to distrust even the Almighty and disbelieve the All-true this he must never know. It becomes neither the dignity of his calling nor the faithfulness of his God.
II. A reason assigned "Thou art Mine." These words were spoken to Israel after the flesh, and to them they still remain a covenant of peace, sure and steadfast for ever; yet as the relations named Creator, Redeemer, and Saviour are not peculiar to them, but are enjoyed in the same degree by every believing heart, we may safely take to ourselves a share in this animating promise. The certainty of the believer's hope does not depend on our holding God, but on God's holding us, not on our faithfulness to Him, but on His faithfulness to us.
III. A protection promised. This does not consist in any absence of trial and danger; the expressions of the text rather imply their presence, many in number and various in kind. The protection promised in the text consists in the constant presence with the soul of its unseen but Almighty Saviour. The preserving hand will never be withdrawn, and the grace of the Comforter will strengthen and cheer the soul still in its sorest times of difficulty and distress.
E. Garbett, The Soul's Life,p. 204.
References: Isaiah 43:1. R. Thomas, Christian World Pulpit,vol. xxvi., p. 88. Isaiah 43:1-4. Spurgeon, Sermons,vol. xxxii., No. 1895.