"A flood of healing energy flows from you into injured creatures around you. You restore up to 700 hit points, divided as you choose among any number of creatures that you can see within range. Creatures healed by this spell are also cured of all diseases..." This seems to imply that a target must be healed of damage to cure its diseases. It seems weird to say that undamaged, diseased people must first injury themselves, or have someone else injure them, in order to have their diseases cured.

They need not be injured for you to use points from this to heal them, it just won't restore hitpoints beyond their maximum and, if they are diseased, cure their disease

Is Mass healing better over just Heal? I am trying to figure out what healing spells for my Soul Divine Sorcerer

Heal is a 7th level. This is a 9th, those are generally just the strongest spells in the game

Quote from Sniperwes20 >>

This spell basically is a whole party heal for your cleric. Lets say your party has 5 members, and it is balanced with spell-casters, and fighters. Your whole party is now back up to nearly full heath in the middle of a boss fight. You also can use it to restore 1 hit point to 700 towns people and cure all disease in a town. Lastly, if you are a life domain cleric you can restore 12 hit points to 700 people, basically healing an entire army in the middle of a battle.

 I was skeptical about stuffing that many people into a line of sight for 60' but the math works out. 60' radius = 11,309ft2, spell says creatures you can see and visual arc is 120 degrees which is 1/3 of 360, so you have 3770ft2 to put 700 people in. If you space them out evenly that means they get 5.38ft2 each, which is plenty of room between humanoids so all of them can be seen by the healer, assuming the healer is on a slight rise like a pitcher mound or standing on a bench.