Rule 120.4d

Finally, the damage event occurs. Example: A player who controls Boon Reflection, an enchantment that says “If you would gain life, you gain twice that much life instead,” attacks with a 3/3 creature with wither and lifelink. It’s blocked by a 2/2 creature, and the defending player casts a spell that prevents the next 2 damage that would be dealt to the blocking creature. The damage event starts out as [3 damage is dealt to the 2/2 creature, 2 damage is dealt to the 3/3 creature]. The prevention effect is applied, so the damage event becomes [1 damage is dealt to the 2/2 creature, 2 damage is dealt to the 3/3 creature]. That’s processed into its results, so the damage event is now [one -1/-1 counter is put on the 2/2 creature, the active player gains 1 life, 2 damage is marked on the 3/3 creature]. Boon Reflection’s effect is applied, so the damage event becomes [one -1/-1 counter is put on the 2/2 creature, the active player gains 2 life, 2 damage is marked on the 3/3 creature]. Then the damage event occurs. Example: The defending player controls a creature and Worship, an enchantment that says “If you control a creature, damage that would reduce your life total to less than 1 reduces it to 1 instead.” That player is at 2 life, and is being attacked by two unblocked 5/5 creatures. The player casts Awe Strike, which says “The next time target creature would deal damage this turn, prevent that damage. You gain life equal to the damage prevented this way,” targeting one of the attackers. The damage event starts out as [10 damage is dealt to the defending player]. Awe Strike’s effect is applied, so the damage event becomes [5 damage is dealt to the defending player, the defending player gains 5 life]. That’s processed into its results, so the damage event is now [the defending player loses 5 life, the defending player gains 5 life]. Worship’s effect sees that the damage event would not reduce the player’s life total to less than 1, so Worship’s effect is not applied. Then the damage event occurs.