About Lemaitre: Looking up Hubble's Law on the Wikipedia at 
http://en.wikipedia....Hubble%27s_law:
Quote
Although widely attributed to 
Edwin Hubble, the law was first derived from the 
General Relativity equations by 
Georges Lemaître in a 1927 article where he proposed that the 
Universe is expanding and suggested an estimated value of the rate of expansion, now called the 
Hubble constant.
[3][4][5][6][7] Two years later 
Edwin Hubble confirmed the existence of that law and determined a more accurate value for the constant that now bears his name.
[8] The recession velocity of the objects was inferred from their 
redshifts, many measured earlier by 
Vesto Slipher (1917) and related to velocity by him.
Now the Wik is not unchallengeable of course, but it's probably a place to start.  Consider "first derived from the 
General Relativity equations by 
Georges Lemaître in a 1927 article". This suggests that whatever religious significance he might or might not have seen in Hubble's Law, the paper is based on scientific analysis, not on dictates from faith. Also "The recession velocity of the objects was inferred from their 
redshifts, many measured earlier by 
Vesto Slipher (1917) and related to velocity by him." is of interest. Comparing tis with the statement about Lemaitre, I gather that the movement of the galaxies away from each other was observed prior to Lemaitre, and Lemaitre's contribution was to show how tihs motion could be described, or perhaps explained, within the context of  General Relativity. A very substantial; contribution. 
While this refers to Hubble's Law rather than the Big Bang, obviously they are related. 
I grew up at a time when Fred Hoyle and the Steady State Theory still had a substantial, although I think minority, following. To the best of my knowledge, no one I ever knew, theist, agnostic, or atheist, was holding his breath and planning on changing his religious views when the issue was settled. PassedOut made a similar observation above, as did brothgar.