To get all the miracles you need to rescue 1 guy saint Urbain.
You can find him in world 4-2. If you kill the first reaper jump down and go trough a door where you see glowing stones, than you must see a hole in the ground. Jump in that hole and there you'll find saint Urbain. Be carefull, there is a black phantom with dual katanas down there, after you talked to saint Urbain he will move to the nexus and there you can buy spells from him.
Here is a list from all the miracles you need for the throphy.For some miracles you need souls to learn them,and for the most miracles you need a demon boss soul to learn them.
Heal: Disciple of God or saint Urbain: Costs 5000 souls.
Antidote: Disciple of God or saint Urbain: Costs 3000 souls.
Evacuate: Disciple of God or saint Urbain: Costs 20,000 souls.
Subdue Soul: Disciple of God or saint Urbain: Costs 3000 souls.
Recovery: Saint Urbain: Costs 3 Colorless Demon Souls (Primeval Demon).
Rage of God: Saint Urbain: Costs 1 Dragon Soul (Dragon God).
Banish: Saint Urbain: Costs 1 Yellow Soul (Old Monk).
Slow Recovery: Saint Urbain: Costs 1 Swollen Soul (Adjudicator).
Revival: Saint Urbain: Costs 1 Hero Soul (Old Hero).
Anti-Magic Field: Saint Urbain: Costs 1 Storm Soul (Storm King).
Cure: Saint Urbain: Costs 1 Wriggling Soul (Leechmonger).
Resurrection: Saint Urbain: Costs 1 Pureblood Soul (Maiden Astraea).
Good luck :)