You teach that Daniel 9:25 gives us a timeline for Christ's Second Coming that begins with the rebuilding of Jerusalem's wall, but others say this verse teaches the timeline begins with a re-establishment of Israel's justice system. How do I know which interpretation is correct?
First, let's look at Daniel 9:25:
The issue in question is when do we begin counting the "seven weeks and sixty-two weeks?" The verse says we should begin the timeline when something is rebuilt, specifically Jerusalem and its wall and plaza. As you say, some teach that it is not the wall that begins the timeline but the re-establishment of the Jewish courts of justice operating in Jerusalem.
The question centers around a single Hebrew word in Daniel 9:25. The Hebrew word used for wall (or moat) is charuts, which can be translated in one of three ways depending on context. First, it can mean a judgment or decision, as used in Joel 3:12-14.
Secondly, it can mean gold, as in the last word used in Psalm 68:13:
Lastly, it can mean a wall or barrier (like a moat) as it has been translated in Daniel 9:25 by all English Bibles.
Which one of these three possible translations should be used for Daniel 9:25? We can answer the question by trying each option in the context of the verse and checking the result. What is the context of Daniela 9:25? Clearly, the overall context of Daniel 9:25 is speaking of a construction project. Jerusalem is being rebuilt, and several features of the city are described. I
With that context in mind, we see that it (i.e., Jerusalem) will be rebuilt with a plaza (i.e., an open space) and a charuts. So whatever charuts means, it must refer to something that is built in the same sense (and timeframe) as the rest of Jerusalem. Now let's consider each of the three possible meanings of this Hebrew word in that context.
First, Jerusalem will be rebuilt with plaza and gold. This is logically possible, but historically we know that Jerusalem was not, in fact, built with gold. It was built with stone and wood, like any other city of that day. So the word can't mean gold.
Secondly, Jerusalem will be rebuilt with plaza and decision (or judgment). This statement makes no grammatical nor logical sense. The word must describe the building of the city itself. Notice that the first word is plaza, which describes a physical feature of the city, and therefore the second word would logically also pertain to a physical feature of the building. Interpreting the word to mean judgment or decision does not follow naturally from the context.
Finally, we can interpret the word as wall (or moat or barrier), and in doing so we arrive at a conclusion that is accurate to the context and accurate to history. You can learn much more about this prophecy in Daniel and how to accurately interpret the prophecy in chapter 9 by listening to our Revelation series, especially Lesson 5C, found here:
Note: The accompanying visual aids in Lesson 5C are also very helpful in understanding the teaching.