How would I be able to judge if what I am doing is right or wrong? There are some things that are not in the Bible, or let us say there are things that the Bible does not fully cover as a topic. A good example can be pornography. Although the Bible doesn't say the word, it is explained by the Bible that it is sinful. People sometimes make excuses that such and such is not in the Bible, so it is okay to do it. They tend to understand the Bible with few words and phrases and yet fail to understand the whole thing.
There are things in life that are difficult, such as making descicions. How will one know if something is right? For example, my parents told me that I should't date people of a different culture. Looking at the Bible, I thought of obeying our parents for it is right (Ephesians 6:1). But I want to point out also why can't I do so? What if I argue that I want to date for the sake of experience and learning? Is that bad also? I have opened the topic with my parents, and I understand their explanation to me also.
Another example can be frequent dating of the opposite sex. One is for the sake of getting to know each other and will progress beyond the friendship stage. The other is for the experience of dating or gaining friends. This is said to be wrong because you are not true to yourself or even cheating (assuming you prefer the other person). I admit I get confused just thinking about it sometimes.
There are some more I would like to mention, but I do hope you understand what I mean. I am being troubled by situations like this, and though I pray for God's wisdom and His help, I still don't know what to do, or I end up wondering if I am on the right path. Maybe I am being tested regarding the decisions I will make. Or maybe I should at least take a chance and learn again through experience. I don't know. Maybe life is just hard as it can be until Jesus comes again.
I think you are more aware of the answers to your questions than you want to admit. It is true that some topics are not mentioned by name in the Scriptures, but as you realize, it doesn't mean we can't figure out whether those things are right or wrong. The word "understand" in the Scriptures means to reason, to put facts together. Thus the command, "Therefore do not be unwise, but understand what the will of the Lord is" (Ephesians 5:17), means far more than just reading your Bible.
Your example regarding pornography is interesting because even people who don't follow the Bible know it is wrong. They hide it because they know it will cause problems if it is found. If the "heathen" knows the right and wrong in this matter (Romans 2:14-15), why is it a difficulty for a Christian? See A Look at Pornography and The Problem of Private Lust for details on why it is wrong.
You didn't quote Ephesians 6:1 correctly. It says, "Children, obey your parents in the Lord, for this is right" (Ephesians 6:1). The phrase "in the Lord" is important because it limits the obedience to those things that God authorizes. Nor does obedience preclude asking questions to gain a better understanding. Our Lord wants obedience, but He also invites discussion. "Come now, and let us reason together" (Isaiah 1:18).
You state that your parents are prejudice against other cultures and do not want you to date outside your culture. Upon what verse is that based? There are reasons for limiting dating to those who hold similar moral standards to your own and to strongly consider someone who the same religious values as you do. But there is no absolute restrictions in the Scriptures, just recommendations for better choices. Remember that Moses married an Ethiopian (Numbers 12:1), Boaz married a Moabite woman (Ruth 4:10), etc. Where problems came in were those who were already disobedient to God who then married those not interested in God, such as Esau's marriage to Canaanite women (Genesis 36:2), or Ahab's marriage to a Sidonians (I Kings 16:31).
I'm not certain what you were meaning by dating just for friendship. If both parties know that there is no commitment and you are just spending time together as friends, then there is no problem. But if you let another person believe that this could be more than friendship but have no intentions beyond personal entertainment, then that is misleading someone for your own gain. Again, the concept isn't hard -- it is a matter of being open and honest.
I missed that quote in Ephesians. I overlooked the word "in the Lord." Surely parents won't teach their child to do wrong. No wonder it says "in the Lord".
I guess your last paragraph is true. But I can't just walk up to the people and frankly say that we are dating just to be friends, right? That would look really awkward. So does that mean I have to be smart enough whether the person I am with has other intentions beyond friendship? That will be hard for them, and maybe even for me. My parents even restrict me from just even mingling with them. I understand their explanation, so does that mean I have to really restrict myself to staying within my "comfort zone"? My parents also discussed this with me many times already, maybe I just can't tell friendship from dating to being more than friends.
In your example of the people in the Bible, there are problems that arose, like that of Esau. How about your example of Moses? (I have yet to read the verses). I also would like to add Naomi's recommendation for Ruth.
Conscience may have something to do with whether what one is doing is right or wrong. Like pornography, if it isn't a sin, why do people tend to hide it? Is that what the Scripture is pointing out? I think I am getting it now. I am just thinking if there are other examples.
Right and wrong are fixed answers. Pornography is wrong because God says not to persue lust. "For this is the will of God, your sanctification: that you should abstain from sexual immorality; that each of you should know how to possess his own vessel in sanctification and honor, not in passion of lust, like the Gentiles who do not know God" (I Thessalonians 4:3-5). The fact that people hide pornography is an indication that they understand it is wrong, even if they can't properly express why it is wrong. Our conscience, then, is to function as an alarm bell. It might not be properly set. It might go off when something isn't wrong, or it may fail to go off when it should. But if it goes off, we should not ignore it. "Do you have faith? Have it to yourself before God. Happy is he who does not condemn himself in what he approves. But he who doubts is condemned if he eats, because he does not eat from faith; for whatever is not from faith is sin" (Romans 14:22-23).
I would comment more, but I just wasn't able to follow what you were asking.