Short Version:
The 5e rules state that a player can substitute material components with a focus. Could the player provide the actual material instead?
If so, could a Divine Soul Sorcerer/Paladin use the holy symbol engraved on his shield to cast Spirit Guardians (that counts as a sorcerer spell) without having to drop/sheathe his weapon and pulling out his focus that explicitly names a holy symbol as the material component?
If so, would that be so strong since in my understanding the necessity of different foci slows down some of the rather strong multiclass options.
A player of my group came up with a rough levelup-plan for his character in our upcoming campaign. He will be a Sorcerer/Paladin. All his paladin spells' somatic and material components will be dumped into the shield, because of other discussions on this site, this seems to be the way it is.
Now, his Divine Soul uses Cleric spells as a Sorcerer spells and hence their material component should be covered by a focus or a pouch, but he argues that the DND5e Basic rules state:
A character can use a component pouch or a spellcasting focus ... in place of the components specified for a spell.
So he argues that he can use his holy symbol engraved on his shield to cast "Spirit Guardians" as the Divine Soul and I am very inclined to let him do it, because I like it when players come up with smart character ideas that have an instantly comprehendable role playing aspect. (yeah, sure, there are some very well played barbarian wizards out there, but everyone gets the Aasimar Divine Soul Paladin instantly).
The Divine Soul Conquest Paladin seems to be strong as it is and now letting him cast holy symbol cleric spells with his weapon drawn could become a tad strong. Well, I like that it's not a Sorlock engulfing everything in darkness and sniping away while everyone else can't do anything useful and besides the damage potential from the Scourge Aasimar trait and Spirit Guardians it seems more like a robust support but still.
Is this holy symbol material a way around the slowing down of the multiclassing impact? I think about the oftentimes talked about cleric druid who is a beast of a healer but has to take into account the changing of weapons/foci.