Saradomin's Spellbook

Start
Talk to the Holy Mage in the Wizards' Guild. He is on the ground floor. He will ask if you want to have Saradomin's spells.

Dialogue 1

 * You: Hello there.
 * Holy Mage: Hello there too. Would you like to have Saradomin's spells?
 * You: Option 1: Sure!
 * Mage (option 1 without 70 Prayer): You are not ready yet.
 * Mage (option 1 with 70 Prayer): Ok. I will teleport you to a place where you can learn it.
 * You: Option 2: I come from Zamorak, and I wish to cleanse Saradomin from this land!
 * Mage (option 2): Burn in Saradomin's wrath, be banished from my sight! (Teleports you to the Demonic Ruins)
 * You: Option 3: No thank you.
 * Mage (option 3): Ok, fine then. Come to me if you would want to.

The Holy Church of Saradomin
When the holy mage teleports you to the church, you will see some monks. Talk to any of them. They will tell you to get 3 items to complete the ritual for you to get Saradomin's spells. This is a sacred leaf, a bowl of holy lava, and a blessed gem. He will give you a holy bowl to get the holy lava.

Sacred Leaf
To get the sacred leaf, you will need to go through Wildgred Forest. This place is full of level 32 Poisonous thorns and level 74 Leaf trolls. Somewhere in it you will find a sacred leaf bush, but unfortunately a level 121 Leaf troll guard is guarding it. Kill it, and then pick a sacred leaf from the bush.

Bowl of holy lava
You would you brought the holy bowl at this time, because you will need it. Go to the TzHaar Caves, and then, at the wall where the banker is, the is an option (Punch Wall). You can only do this during the quest. You need 70 Strength to punch it. You may fail and take 3 damage. You need five successful punches. Then, go into the hole. You will find that this place is full of holy lava, but the door to go further is blocked by a level 98 Lava guardian. Kill it, then open the door. Use your holy bowl on any holy lava in this place, beware of the level 81 Lava Warriors which are aggressive, and done!

Blessed gem
NOTE: You will need your holy bowl of holy lava, but this is the easiest task. Use a holy bowl of holy lava on the molten glass to get a holy glass. Then, use it on the altar in the Monastery of Saradomin. Then, use the holy symbol on the identical altar. Then, take your holy glass out. It has been blessed.

The Demon
Now, ask the holy mage to teleport you back to the church, and in there, give the items to the monk. A cutscene will happen. The monk will put the items on a holy table, and the symbol of Saradomin glows blue. After a while, it turns red. The holy mage says that he senses something as evil as Zamorak. When you are ready, he will teleport you. There is a portal leading out in case you run out of food. When you are ready, ask him to teleport you. Kill the Level 200 Banished demon, and then... QUEST COMPLETE!

Rewards

 * Ability to use the Saradomin Spellbook
 * Saradomin ancient staff