Denominations — legitimate variety within Christianity vs. counterfeit groups

Denominations are like different denominations of currency — all real money. Baptists, Presbyterians, etc. differ on secondary issues (infant baptism, etc.) but share core Christian doctrine. What would be problematic is a group that denies central tenets of the faith (resurrection, Scripture's authority) — such a group becomes a counterfeit, not merely a different denomination. Mike distinguishes secondary disagreements (fine to have) from gospel-level departures (not acceptable). Some older mainline denominations have drifted from secondary differences to abandoning the gospel itself.