Jorn, God of Winter // Kaldring, the Rimestaff, Moritte of the Frost, and Strionic Resonator

Prerequisites

• Jorn, God of Winter // Kaldring, the Rimestaff on the battlefield
• Moritte of the Frost on the battlefield
• Strionic Resonator in hand or on the battlefield or in the command zone or in exile or in the graveyard or in the library
• Jorn does not have summoning sickness
• Snow permanents you control can tap to produce at least

Steps

1. Declare Jorn as an attacker, triggering its ability
2. Holding priority, activate all mana producing snow permanents you control by tapping them, adding at least
3. Activate Moritte of the Frost by paying and tapping it, copying Jorn's triggered ability
4. Resolve the copy of Jorn's ability, untapping all snow permanents you control
5. Repeat from step 2

Results

• Infinite mana snow permanents you control can produce
• Infinite untap of snow permanents you control