testimonial / testimony

My take on it..

He is giving testimony (Evidence in support of a fact or assertion; proof.)

or

He is giving a testimonial.



Both will work but no pronoun with testimony.

Agree with Parados, except to me "giving a testimonial" is not something you would do in respect of a religion.
More a washing powder or something like that.

"a testimonial of faith", perhaps.

I feel that there is a slight difference. Would a testimonial suffice in a court of law? It seems to me that it would not. It seems an expression of opinion, not one of fact. While a great deal of testimony is far from fact, its intent is that it should be.