Why is there added: He descended into hell?

In my greatest sorrows and temptations I may be assured and comforted that my Lord Jesus Christ, by His unspeakable anguish, pain, terror, and agony, which He endured throughout all His sufferings but especially on the cross, has delivered me from the anguish and torment of hell.

Proofs

• In my greatest sorrows and temptations I may be assured and comforted that my Lord Jesus Christ, by His unspeakable anguish, pain, terror, and agony, which He endured throughout all His sufferings (Psalm 18:5–6; Psalm 116:3; Matthew 26:36–46; Matthew 27:45–46; Hebrews 5:7–10)
• but especially on the cross, has delivered me from the anguish and torment of hell. (Isaiah 53)