This clever pairing turns a simple loop of life and growth into a devastating storm of damage. By enchanting Shalai and Hallar with Light of Promise, you establish a self-sustaining feedback loop: any initial lifegain triggers Light of Promise to place a +1/+1 counter on Shalai and Hallar, which in turn causes Shalai and Hallar's second ability to deal damage to an opponent and gain you life. That new instance of lifegain immediately restarts the cycle, allowing you to continually grow your creatures while overwhelming your opponent with infinite damage.