Should I make commander with 4 holy a prophet?

[Taqwus]

Yes, it depends.
If you're Pythium or Marignon, for instance, you may get a national hero with an intrinsic Holy-5 (!). It's also not that hard for Pythium to Smite en masse even without that hero or an Arch-Theurg prophet, because Communion boosts holy/unholy power as well.
If you lack easy access to Communion and don't have such a national hero (or have only one but want more smiters without Communion or boosting items), however, it may be more interesting to you to prophetize that Holy 4.