there but for the grace of God go I

There are several variants of this phrase, but all make reference to the same concept: an admission of humility that were it not for the work of God's grace (and perhaps also one's upbringing among those also formed in God's grace), any number of trials or tribulations could have befallen a person. The original is most often attributed to St. Francis of Assisi, who may well have been quoting or paraphrasing the words of the Apostle Paul in 1 Corinthians 15:8–10, which states, "Last of all, as to one born abnormally, he appeared to me. For I am the least of the apostles, not fit to be called an apostle, because I persecuted the church of God. But by the grace of God I am what I am..." It has also been attributed to a mid-16th-century statement by a Protestant, John Bradford: "There but for the grace of God, goes John Bradford", in reference to a group of prisoners being led to execution.

来源：wiktionary