Divine Inspiration (Tier 1) can be bought from the Zamorakian quartermaster and the Saradominist quartermaster during the Battle of Lumbridge for 400 Renown. A player can "Drink" this item and then the amount of divine tears they receive from the skilling plots on the battlefield is increased by 50% for 10 minutes. After the week 9 vote, the store price was reduced to 380 Renown.
Currently it seems that Divine Inspiration stacks multiplicatively with yellow nodes, which give triple tears, but does not stack with the 1 bonus tear from tokens. If a player has a base tear multiplier of 4, they will gain 3 x 4 x (1+50%) = 18 tears, or 21 tears if the bonus activates as that does stack with yellow nodes.