[This is] the truth from thy Sustainer; be not, then, among the doubters!

The Truth (comes) from God alone; so be not of those who doubt.

(This is) the truth from thy Lord (O Muhammad), so be not thou of those who waver.

(This is) the truth from thy Lord, so be not of the disputers.

The truth is from your Lord, so do not be among the doubters.