The only "biblical" justification that I ever heard Lee give for his obsession with numbers was "Well, you know, there is a book in the Bible called Numbers." There is no biblical justification for UBF's obsession with numbers. There is no justification at all.
A common UBF defense of the numbers obsession when a young recruit gets bothered by it is "Numbers don't matter, blah, blah." Numbers don't matter? Then why obsess with numbers, keep track of numbers, think of ministerial progress only in terms of numbers, have "prayer topics" that consist only of numbers, threaten punishments if a numbers goal is not reached and judge members' spiritual health by their performance numbers. In other words, if "numbers don't matter," then why act as if numbers are everything?!
The proudest parents in UBF are those whose children "feed [insert number here] sheep."
The thing is, I think most UBF members hate this ministry of numbers and know that it is wrong, counter-productive and self-defeating, but for various dysfunctional reasons they and especially their leaders work to preserve this "spiritual legacy" of Lee. Henry Kriete, who seems to have touched off much soul searching and reform within the International Church of Christ wrote in his now famous February 2003 letter:
In my experience many of you, if not most, will agree with what I am saying. Perhaps every last one of you. But why have we not stopped this madness? Why does it go on and on when most of us hate it so? And in our hearts feel guilt, if not shame? Because ‘that’s just the way it is’? No – but because it’s another systemic evil, another pillar in our belief system that must be smashed.
Kriete also wrote extensively about the ICC's own brand of obsession with numbers.