This torah portion is packed with Mitzvot that should be logical to us (as opposed to the Chukim, whose reasons can only be comprehended by God), some are review (as the Book of Deuteronomy which is Greek for “Second Telling”, is usually) and some are new: including agricultural laws, including those of tithing, the Oneness of God and his role as the only thing (for lack of a better term) to worship, certain laws of Kashrut, ignoring false prophets or those who entice you to worship others and the actual penalty for spreading false prophesy or heresy, and various laws of the pilgrimage festivals. Famously the first line of chapter 13 states, “be careful to observe only that which I enjoin upon you: neither add to it nor take away from it”. It is this, I believe what caused sects such as the Karaites to remove themselves from mainstream Judaism, denying Rabbinic texts with the sole acceptance of either the Torah or the entire Tanach. Indeed, Rabbinic Judaism, that which a vast majority of Jews have been a part of in the past two millennia since the Destruction of the Second Temple (the tailend of which we were known as Pharisees) has also made the claim that they weren't adding or subtracting, but rather interpreting the Torah, the crowns of the letters, so to speak. A midrash from the Talmud illustrates this which I will quote here and I suggest you read the article I found on the topic from which I copied the Talmudic quote:
Rav Judah said in the name of Rav, When Moses ascended on high he found the Holy One of Blessing, engaged in affixing coronets to the letters.  Said Moses, "Lord of the Universe, Who stays your hand?" He answered, "There will arise a man, at the end of many generations, Akiba b. Joseph by name, who will expound upon each tittle heaps and heaps of laws." "Lord of the Universe," said Moses; "permit me to see him." He replied, "Turn around." Moses went and sat down behind eight rows [and listened to the discourses upon the law]. Not being able to follow their arguments he was ill at ease, but when they came to a certain subject and the disciples said to the master "Whence do you know it?" and the latter replied "It is a law given to Moses at Sinai" he was comforted. Thereupon he returned to the Holy One of Blessing, and said, "Lord of the Universe, you have such a man and you give the Torah by me!" He replied, "Be silent, for such is my decree." Then said Moses, "Lord of the Universe, you have shown me his To rah, show me his reward." "Turn around," said He; and Moses turned around and saw them weighing out his flesh at the market-stalls. "Lord of the Universe," cried Moses, "such Torah, and such a reward!" He replied, "Be silent, for such is my decree." 
My final thought on this week's parasha is regarding the false prophets. We studied, in one of my Talmud classes, that we are to listen to a true prophet, "migdar milta shani" that a true prophet in cases of national emergency, can override certain Torah laws. In fact, the Torah law that this prophet temporarilly cancelled is within this Torah portion. Actually, so is the law that one cannot add or subtract from Mitzvot. So three of them come into play from this very torah portion. In Masechet Yevamot, we read about the account in, I believe, the First Book of Kings, where Elijah the prophet has a standoff with evil queen Jezabel and the Priests of Baal on Mount Carmel in the recently bombed port city of Haifa. In order to show that God was the only God and the only One to whom we may sacrifice (or in the past 2,000 years, the only One to whom we may direct our prayers), he ordered two altars be erected on the mount, one dedicated to Baal and one to Hashem. Whichever altar became ignited by heavenly fire would be proclaimed as the true God. Elijah even gave the Priests of Baal a head start and they were unable to do anything for an hour. Elijah said a simple prayer to Hashem and a heavenly fire ignited the altar. I should mention that the altar in Solomon's Temple was also ignited by heavenly flames. This possibly suggests heavenly sanction for this act of erecting a bamah in the high places, especially considering tha the Second Temple was in existence at the time. Migdar Milta Shani...
That's it, Shabbat Shalom,