[By] what 'other things' are we justified?
If you have an e-version of the Bible the search takes seconds.
Searching "
justified by" in the NT results in ten mentions in 9 verses. Four of them are negatives, we are NOT justified by works or the Law. Of the remaining 8 examples, one of them says we are justified by grace (Tit. 3:7) and one of them says we are justified by works, not just faith (Jms. 2:24). The remaining four mentions state "
justified by faith" (Rom. 3:28 & 5:1; Gal. 2:16 & 3:24; but there is some controversy pertaining to one of them because some translations say, "
faith of Christ," while the most of the modern versions say, "
faith in Christ" and a transliteration of the Greek results in "
faith from Christ."
For the purposes of
this post it is clear justification by faith is the overwhelming standard both normatively and statistically. The two or three exceptions are statistical outliers. Their normative status can be considered in different ways or various degrees but I, personally, read them as cohesive parts of the whole, not disparate statements intended to conflict with one another.
A New Testament search of only the word "
justified" complicates things because the word is used 24 times and the first states,
Matthew 12:33-37
Either make the tree good and its fruit good or make the tree bad and its fruit bad; for the tree is known by its fruit. You brood of vipers, how can you, being evil, speak what is good? For the mouth speaks out of that which fills the heart. The good man brings out of his good treasure what is good; and the evil man brings out of his evil treasure what is evil. But I tell you that every careless word that people speak, they shall give an accounting for it in the day of judgment. For by your words you will be justified, and by your words you will be condemned.
Words both justify and condemn!

But that particular verse is worded as a "will be" (future) and not an already existing justification. It is predominantly eschatological in nature. The next mention is in the comparison made between the humble, repentant tax collector and the prideful, self-righteous and condescending Pharisee so I will temporarily pass that example as an argument of extremes. The third mention is in Romans 2.
Romans 2:12-13
For all who have sinned without the Law will also perish without the Law, and all who have sinned under the Law will be judged by the Law; for it is not the hearers of the Law who are just before God, but the doers of the Law will be justified.
Doers of the Law will be justified

. Wait. What? Did not Paul say
four times we are NOT justified by works
or the Law? Yes, he did. Paul juxtaposed the "
works of the Law" against "
a law of faith" by which any boast in the Law was excluded, BUT this law of faith that excluded boasting in one's works of the Law did not nullify the Law but
established it

. Paul spent six chapters explaining it

.
Most of the 24 mentions of justification fall within the examples or categories listed above, but two examples stand out apart from those categories. One is Romans 5:9 which states we are justified by the blood of Christ. Romans 8:30 implies we are justified by God because God is repeatedly stated as the one doing the various actions listed (calling, predestining, sanctifying, justifying, etc.).
- Justified (eschatologically) by one's words
- Justified by God
- Justified by faith in Christ
- justified by faith of or from Christ
- justified by grace
- justified by faith that are evidenced by works (or what we might call faith begetting faithfulness).
Scripture states six "
justified by," or five if the Gal. 2:16 text is treated as "
in" and not "
of" or "
from".
However, for the purposes of this post the main point I'd like to make is it does not take very long to find and read ALL mentions of justification. They can all be covered in one (admittedly lengthy) post. Because of that fact all the denominational/doctrinal biases can also be recognized (and separated and excluded), along with all the selective appeals to scripture that either emphasize one verse over another or pit one against another. In the age of computers there is no warrant for the kind of disagreement common on that topic (if we stick first and foremost to whole scripture)

.
Let's not forget how we (you and I) got to this point. You asked how the new birth and justification interrelate and I suggested they were co-occurring. Those God regenerates or births anew from above (
gennethe anothen) He
also justifies. Assuming justification is understood as a legal term pertaining to one's ability to stand before the Judge and plead one's case,
* then there is no regenerate person that is not also justified, and there is no justified person that is not also regenerate. Regeneration is not said to
cause justification, nor is the reverse said to be so. God regenerates and God justifies. God does a bunch of stuff (as the Romans 8:30 list indicates) and one of them is justification. Sometimes the many things God does are causally related, but most are correlates, not causes. When it comes to the new birth and justification, I view them as correlates. Every person born anew by God also has an ability to stand before God and plead his/her case because that person is also covered by the blood of Christ shed at Calvary. In that condition there is NOW no condemnation.
To stand before God apart from that covering is instant incineration

(or something equally unimaginable).
*we have several examples of this recently in the news: the federal government could not impeach the POTUS once he's left office because they have no standing to do so, or a state may not exclude a candidate from a ballot in a national election because they have no standing to do so - because they've either violated the candidates due process OR cannot themselves decide an election for the whole country. A person or group must have grounds for a case before the case can be presented. Cases without grounds for presentation never see the insides of a courtroom.
.