The opening mitzvah of parshas Shoftim mandates that courts of law be established throughout the land. That same verse directs the judges to execute "mishpat tzedek"- righteous judgment. Judges are then further instructed not to pervert judgment, to not show any favoritism to a litigant by giving him preferential treatment, and to not take a bribe. Then the Torah seems to be repeating itself again when it says (16:20) tzedek tzedek tirdof- righteousness righteousness shall you pursue". Rav Ashi in Sanhedrin (32A) understood the repetition of the word righteousness to teach that circumstances might warrant different "righteous" approaches. There are instances in which the course of righteousness is to pursue justice, din, and other circumstances in which righteousness dictates we pursue compromise, psharah. In addition, the Talmud (ibid) understands "tzedek tzedek tirdof" as an instruction to seek out the best court available.
The Dubner Maggid in his Ohel Yaakov (parshas Mishpatim) has a novel understanding of "tzedek tzedek tirdof". Rather than understand the teaching as addressing judges, he learns the verse as a directive to each individual that in their personal and business affairs they are to be scrupulously careful to ensure that what is theirs is really theirs. In fact, he questions the nature of the dinei Torah that arose in the midbar and suggests that unlike most court cases, in which each individual claims rights and possession, here they were asking the judges to verify and ensure their rightful claim of ownership, with each one saying ,"No! Maybe it is yours".
There is a delicious Medrash (Vayikra Rabbah 27:1) that illustrates this idea. The Medrash teaches that Alexander the Great once visited the community of Afriki and wished to observe its judicial system. Two men came before the king for justice. The first said, "I purchased a plot of land from this man, and when I dug to lay the foundation of a home, I found a treasure buried there. I only bought the land, not the treasure, therefore it is not mine." The seller said, "I too am fearful of the biblical prohibition of ‘lo tigzo"- do not steal' and I too do not want it back unless it is definitely mine." The king (judge) asked the buyer if he had a son, he answered "yes". The seller answered positively to having a daughter. "Wonderful," said the king, "let them marry and share the treasure." This is "tzedek tzedek tirdof"- affirming with certainty that what's yours is really yours.
The Arizal was known to have the ability to identify sins and transgressions of individuals by looking carefully into their face. The Rav of Tzfas, Rav Moshe Galante (1540-1614) once came to the Arizal for his "spiritual check-up", whereupon the latter said "you have safek gezel"- literally you are suspected of thievery/ borderline theft. The rabbi who had a silk business fasted, cried. He then called in all his workers, put a pile of money on the table, and asked if he had cheated any of them. They all answered in the negative and left. The last to leave, a woman, took a few coins. When the rabbi / employer asked why she took the money, she answered "you paid me as a regular worker, and I am a specialist." The rabbi cried for joy that his record was now cleaned. He was able to say about himself "tzedek tzedek tirdof".
The internet can be a wonderful tool to use, but it is also subject to much abuse. Too many are guilty of pirating information that is copyrighted from the internet. Rav Moshe Feinstein zt"l said it is not permitted to copy any item that is being sold by the creator (maker) of that item. Every time one copies it, they are taking away sales from him. "Everyone does it and it really should be permitted (mutar)"- in no way justifies it.
Our children must be taught the definition of plagiarizing and the prohibition thereof. Again, the internet contains much scholarly material. It is also an opportunity to bring much geulah to the world- by giving proper credit to the author and earning the approbation of "tzedek tzedek tirdof".
Applying for scholarships from yeshivot when one doesn't need it (this is often done by hiding income), is stealing from tzedakah, and the practical consequences of not getting a scholarship when one truly needs it, is because of a lack of "tzedek tzedek tirdof".
It is not sufficient to be careful about eating glatt kosher, our money has to be glatt yashar.