I grew up in a Reformed church since I was a kid. In my adulthood as I become more concerned with my spiritual health, I increasingly expect theology to provide at least a rich enough vocabulary of the spiritual life of a believer that I can latch into and correlate them with aspects of experience in my spiritual life (which is given to me by Christ through faith).
After a decade or so studying and reading, I found that compared to Catholicism (which has a rich store of concepts in its spiritual and mystical theologies) when pushed for clarity, Reformed pastors and teachers keep going back to concepts such as "godliness", "Christlike-ness", "ongoing sanctification" which (despite having REAL referents because Jesus and God are real) is linguistically CIRCULAR since those concepts go back to the theology of God and to Christology, thus creating a wall that separate theology from philosophy/psychology in the area of spirituality. In contrast, Catholicism since time immemorial (especially since St. Augustine) has been self-consciously breaking the wall by integrating theological discussion with philosophy & psychology so that referents of spiritual life concepts such as "godliness", "Christlikeness", and "ongoing sanctification" don't remain ontologically in the realm of the intellect, i.e. remain concepts (albeit having REAL referents to God).
If theology is to have any relevance beyond remaining in the ivory tower, there needs to be a spiritual theology that provides clarity to abstract concepts so it can be "incarnate" (practically real) in a believer's daily life. Thus, if "maturity" can stand in for "godliness" then it is a better term (from spiritual theology perspective) since it's more concrete descriptively, something that humans can have a handle of, in philosophy & psychology. But I found out from experience discussing with Calvinists that most seem to have an aversion to breaking this WALL that separates theology of God/Christ from something that can be experienced and described by the servants of theology, namely philosophy and psychology. They would typically say that Christians are not supposed to pollute theology with humanism. But how can spiritual theology NOT having a philosophical/psychological conceptual tool to describe progress in a believer's spiritual life?
For an evangelical introduction to spiritual theology that specifically connects the theology of sanctification with psychology, please watch/read a 2014 video (transcript included) of a talk at Biola by John Coe, Professor of Philosophy and Spiritual Theology / Director of the Institute for Spiritual Formation at Biola University: Spiritual Theology for the Church.
I am sometimes puzzled with some Calvinists / Reformed believers who insist that no one is righteous but God, EVEN after conversion, sanctification, and resurrection of the believer! This is often characterized by the theological concept of imputed righteousness and alien righteousness which emphasize that righteousness remains solely God's possession forever (but never ours), and they would cite verses like Rom 3:10-12 and interpret them to hold true even when we are in heaven!
My puzzle comes when I come across Bible verses that imply God working in us (during sanctification stage) to increase something within the believer. Example: Phil 1:6,9-11 (CSB):
6 ... he who started a good work in you will carry it on to completion until the day of Christ Jesus. ... 9 And I pray this: that your love will keep on growing in knowledge and every kind of discernment, 10 so that you may approve the things that are superior and may be pure and blameless in the day of Christ, 11 filled with the fruit of righteousness that comes through Jesus Christ to the glory and praise of God.
Later in the letter (Phil 2:13, CSB), Paul reiterates about God's work:
For it is God who is working in you both to will and to work according to his good purpose.
This "growing" and "filling" language implies something that is ontologically REAL within the psychological space that increases within a believer, which is the result of God's work (with our passive cooperation since according to Calvinists all we can do is not rebel). This language also implies "progress" (see a related question).
Sensitive / philosophically minded readers will ask: what is this something within us that God produces within us progressively to enable us "to will and to work according to his good purpose" more and more easily?
So my question to Calvinists / Reformed is this: what is the proper term in spiritual theology (a term that is MEANINGFUL, RELATABLE, and DESCRIBABLE to a human) for the aspect that God increases within us during our sanctification? If not righteousness, can it be called holiness (cf Rom 6:19, NIV)? Or is there no unifying theological term but leaving it to individual fruits (love, joy, etc.) as in Gal 5:22-23? Or do Reformed theologians use a term that is not in the Bible such as virtues for this something?
Some comments have suggested "godliness", "Christlike-ness", and "ongoing sanctification" which are of course perfectly fine as a theological term, but those concepts leave the correlational hard work to poor believers who are untrained theologically to correlate those theological concepts to the realm of philosophy and psychology that they can latch on in daily spiritual life. So while I can accept those as correct answers, I have updated the question to "spiritual theology term" in order to induce answers that can provide synonymous terms which are more pertinent to human experience on the human side of the WALL (see "The background" section).
Secondary questions (which is nice to be addressed in an answer, but not strictly asked for, to keep this Q from being too broad):
- How do we discern the result of God's working in us, even if indirectly (through its effects)?
- If this process does not finish when we die, what happens to God's promise in Phil 1:6? How does God bridge the gap between a faithful with lots of sinful habits to the finished version of that faithful that fits for heaven? Does God simply snap his finger like magic and finish the work without our involvement at all?