God choses those who choose him. Its not a causal relationship, involving before and after. Thats the mistake, its not on a time line. Its simultaneous.
Its a matter of deductive relationship, not material cause and effect.
"And whomsoever Allah causes to err, you shall by no means find a way for him." Koran 4:88
By no means implies impossibility, so therefore it is an a priori truth. Its a matter of analytic relationship, rather than synthetic.
Modal logic would say "It is impossible that A and not-A" and also "If A then A, necessarily".
A being 'guidance'. Those who choose are chosen, necessarily, and vice versa, the chosen are by definition the ones who choose.
Its like asking which came first "1+1=2", or "2=1+1".
So asking which came first, the chosen or the chooser, is a category mistake.
Choosing is something like a performative utterance:
"Performativity is a term for the capacity of speech and communication not simply to communicate but rather to act or consummate an action, or to construct and perform an identity. A common example is the act of saying "I pronounce you man and wife" by a licensed minister before two people who are prepared to wed (or "I do" by one of those people upon being asked whether they take their partner in marriage). An umpire calling a strike, a judge pronouncing a verdict, or a union boss declaring a strike are all examples of performative speech."