The Text
The Government of the Federation or of a State shall not adopt any religion as State Religion.
Source · Constitution of the Federal Republic of Nigeria, 1999, as amended · §10
All sections in Chapter I — General Provisions
Methodology
Tier 1 · primary
Courts. Gazettes. National archives.
Tier 2 · corroborating
OCCRP. HRW. BudgIT. TheCable.
Redline
Wikipedia is never a source.