Steward of the Harvest, Singing Bell Strike, and Serra's Sanctum

Prerequisites

• Steward of the Harvest on the battlefield
• Singing Bell Strike on the battlefield
• Serra's Sanctum in exile

Steps

1. Activate the creature with Singing Bell Strike attached using Serra's Sanctum's ability by tapping it, adding at least seven
2. Activate Singing Bell Strike by paying , untapping the creature
3. Repeat

Results

• Infinite white mana