Cast Whitemane Lion by paying 0 and 2 life due to Defiler of Faith and Oketra's Monument.
Defiler of Faith and Oketra's Monument trigger.
Resolve the Defiler of Faith trigger, creating a 1/1 Soldier creature token.
When the Soldier enters, Healer of the Pride triggers, causing you to gain life.
Resolve the Oketra's Monument trigger, creating a 1/1 Warrior creature token.
When the Warrior enters, Healer of the Pride triggers, causing you to gain life.
Resolve Whitemane Lion. When it enters, it and Healer of the Pride trigger.
Resolve the Whitemane Lion trigger, returning it from the battlefield to your hand.
Resolve the Healer of the Pride trigger, causing you to gain life.
Repeat.
This ingenious loop turns a single white feline into a self-sustaining army by leaning on cost reducers and trigger payoffs. With both Defiler of Faith and Oketra's Monument on the board, you can cast Whitemane Lion for completely free—paying life instead of mana to cover its reduced cost—while simultaneously churning out a Soldier and a Warrior token every single time it enters. Those tokens, along with the Lion itself, continuously trigger Healer of the Pride to pad your life total as the Lion bounces itself right back to your hand, ready to be cast again and repeat the entire spectacle.