An Order Domain Cleric that has Silvery Barbs (from being in Silverquill or through the Fey Touched feat) can use cast Silvery Barbs using a Cleric spell slot as a reaction to give an enemy disadvantage on some attack roll, ability check, or saving throw, then target an ally to give them advantage on their next attack roll, ability check, or saving throw, and then trigger Voice of Authority to allow that same ally to make an attack roll with advantage as their own reaction. With just a single 1st level spell slot.
Furthermore, if they're actually an Order Domain Cleric from the Quandrix college that takes the Fey Touched feat to get Silvery Barbs, in addition to all of that stuff listed above, they can cast Vortex Warp on a the enemy to teleport it up to that ally, force them to reroll the saving throw through Silvery Barbs if the succeeded on it, and then allow the Barbarian, or Paladin, or Rogue to make a melee weapon attack on them (potentially stacking smites, or sneak attack, or rage damage on the attack). Granted, this does take a 2nd level spell slot on top of the 1st level spell slot (and two reactions) to get to work, but it is still an effective combo and would be incredibly annoying if spammed by the players.