Justification has its basis on the clean VS. unclean idea found in Torah. A person who has not touched a corpse or ate with Gentiles has kept himself clean, though not technically (he may be covered with road dust!), but for purposes of Torah, is so, in the ritual sense.
Unclean people could not enter the camp. So in the following, the believer has been found clean for entry purposes into the group known as the People or Friends of God:
Romans 4:3
For what does the Scripture say? "Abraham believed God, and it was credited to him as righteousness."
Romans 3:28
For we hold that a person is justified by faith apart from works prescribed by the law.
James 2:24-25
24 You see that a person is justified by works and not by faith alone. 25 Likewise, was not Rahab the prostitute also justified by works when she welcomed the messengers and sent them out by another road?
So justification is the ritual of checking and finding a person compliant. The just person is found to be just.
The accompanying ritual of MAKING a person compliant is also found in Torah, the ritual of CLEANSING. This ritual is called, unsurprisingly, justification. You will find that that IS the use of the word here :
1 Corinthians 6
11Such were some of you; but you were washed, but you were sanctified, but you were justified in the name of the Lord Jesus Christ and in the Spirit of our God.
Romans 8
28And we know that God causes all things to work together for good to those who love God, to those who are called according to
His purpose.
29For those whom He foreknew, He also predestined (pre planned?)
to become conformed to the image of His Son, so that He would be the firstborn among many brethren;
30and these whom He predestined, He also called; and these whom He called, He also justified; and these whom He justified, He also glorified.
Washing, sanctification and justification are reiterations of the efforts God makes to cleanse a person.
In summary, a justified person is a person who has made efforts to be found acceptable. And God justifies, makes efforts to keep a person in an acceptable state through washing with His Word.
The practical application is to find out what is one being cleansed of, either by his own efforts or when God cleanses.
The answer is: the person is being cleaned from living for self.
When Jacob lived in the Canaan, he and his family were living for self. Out of ignorance, it is true.
To reveal this state of affairs, God caused a chain of events to occur that landed Israel in slavery to Egypt. Just as dusting causes fingerprints to jump out, slavery to Egypt caused the state of God's people to jump out: they were living for themselves.
God had designed men to be fulfilled only when they served others. Just as the purpose of a horse is fulfilled only when he is subdued and trained to carry a rider.
Is it right if a man buys a horse and cares for it only to find that it keeps kicking down the fences and breaks out to find ways to satisfy its appetites?
Unjustified man is in that state. He is God's child, yet he does not cry out to be fed, but makes his own way in life. What he finds, especially in Egypt, is a hard task master extracting work and giving back poor returns.
When God took Israel out of Egypt, He expected Israel to depend on Him for everything. They could only live if they obeyed Him without questioning, did not complain when He withheld food and water, told them to risk their lives in battle.
He had put Abraham through the same testing, and Abraham had slowly learned how to follow God.
See the stages:
God puts different people in different situations hoping they will seek him, because He is not far from His children. The seeking is the effort from the person which justifies him.
Those who seek Him He will feed with His revelations/Word so that gradually they learn what He requires. This is God's work of justification.
At the end of the process, the believer finds rest from his own labor, as he arrives in the Promised Land, rests in Christ, sharing in what remains of Christ's work, His body on earth, serving his fellow men.
In summary, justification is the cleansing through self effort by the believer of the dirt of living for self, and the further cleansing by the efforts of God, to fulfill the purpose for which man was created.