John Wesley on Isaiah 50:10

The voice - Of Christ, who is called God's servant, by way of eminency and to intimate that though he was God, yet he would take upon himself the form of a servant. In darkness - Not in sin, but in misery, that lives in a disconsolate and calamitous condition. No light - No comfort. Trust - Let him fix his faith and hope in the mercy, and faithfulness, of the Lord, declared in his word, and in his interest in God, who by the mediation of this servant is reconciled to him and made his God.