In that sense I would like to disagree with SamLowry slightly. Mathematics is about absolute truths. It's just that the absolute truths in mathematics are ultimately of the form "If ... then ...", when you really drill down and formalize them, e.g. "If we work in that system of axioms, then such and such is true". Even more important, mathematics is not about the real, physical world we live in, whereas any claims of the existence of a God ultimately are about the world we live in, and therefore different rules apply to them.
Saying Mathematics is about absolute truths is a bit misleading. Like you said, formalization always leads to those "truths" being relative to some system of axioms that itself can only be proven with a different set of axioms, and so on. This isn't to say that there is no such thing as objective truth, it just is unreachable or unprovable from a single set of axioms (i.e. Gödel's incompleteness theorems). Deductive proofs are an idealized subset of a much more interesting class of questions where uncertainty is given first-class status. Bayesian analysis is an excellent framework in which to express formal model comparison in the face of uncertainty, though we are forced to make our assumptions explicit (a good thing, in my opinion).
I also disagree that Mathematics is not about the "real, physical world we live in". Even something as detached and abstract as a Turing machine embeds serious physical assumptions, such as a tape cell only containing a single symbol or blank at any given time (this assumption is broken in quantum computing models). Solomonoff, Kolmogorov, and Chaitin have produced an extensive body of work demonstrating that Mathematics itself is an empirical science, requiring the same inferential tools we apply to the "real, physical world" (see Algorithmic Information Theory).