Did Moses write the Pentateuch?

The first 5 books of the Bible are known as the Torah (Hebrew) or Pentateuch (Greek). The books are Genesis, Exodus, Leviticus, Numbers, Deuteronomy. They are commonly referred to as the Law. Authorship is traditionally ascribed to Moses though there is indication in Genesis that Moses is compiling and editing earlier sources.

The Bible confirms Moses as the author of the Pentateuch.

Old Testament

From the Pentateuch

1. Then the LORD said to Moses, "Write this as a memorial in a book and recite it in the ears of Joshua, that I will utterly blot out the memory of Amalek from under heaven." (Exodus 17:14)
2. And Moses wrote down all the words of the LORD. He rose early in the morning and built an altar at the foot of the mountain, and twelve pillars, according to the twelve tribes of Israel. And he sent young men of the people of Israel, who offered burnt offerings and sacrificed peace offerings of oxen to the LORD. And Moses took half of the blood and put it in basins, and half of the blood he threw against the altar. Then he took the Book of the Covenant and read it in the hearing of the people. And they said, "All that the LORD has spoken we will do, and we will be obedient." (Exodus 24:4-7)
3.  And the LORD said to Moses, "Write these words, for in accordance with these words I have made a covenant with you and with Israel." (Exodus 34:27)
4. Moses wrote down their starting places, stage by stage, by command of the LORD, and these are their stages according to their starting places. (Numbers 33:2)
5. Then Moses wrote this law and gave it to the priests, the sons of Levi, who carried the ark of the covenant of the LORD, and to all the elders of Israel. (Deuteronomy 31:9)
6. So Moses wrote this song the same day and taught it to the people of Israel. (Deuteronomy 31:22)
7. When Moses had finished writing the words of this law in a book to the very end, Moses commanded the Levites who carried the ark of the covenant of the LORD, "Take this Book of the Law and put it by the side of the ark of the covenant of the LORD your God, that it may be there for a witness against you. (Deuteronomy 31:24-26)

Elsewhere

1. Only be strong and very courageous, being careful to do according to all the law that Moses my servant commanded you. Do not turn from it to the right hand or to the left, that you may have good success wherever you go. This Book of the Law shall not depart from your mouth, but you shall meditate on it day and night, so that you may be careful to do according to all that is written in it. For then you will make your way prosperous, and then you will have good success. (Joshua 1:7-8)
2. And there, in the presence of the people of Israel, he wrote on the stones a copy of the law of Moses, which he had written. And all Israel, sojourner as well as native born, with their elders and officers and their judges, stood on opposite sides of the ark before the Levitical priests who carried the ark of the covenant of the LORD, half of them in front of Mount Gerizim and half of them in front of Mount Ebal, just as Moses the servant of the LORD had commanded at the first, to bless the people of Israel. And afterward he read all the words of the law, the blessing and the curse, according to all that is written in the Book of the Law. (Joshua 8:32-34)
3. They were for the testing of Israel, to know whether Israel would obey the commandments of the LORD, which he commanded their fathers by the hand of Moses. (Judges 3:4)
4. When David’s time to die drew near, he commanded Solomon his son, saying, "I am about to go the way of all the earth. Be strong, and show yourself a man, and keep the charge of the LORD your God, walking in his ways and keeping his statutes, his commandments, his rules, and his testimonies, as it is written in the Law of Moses, (1 Kings 2:3)
5. But he did not put to death the children of the murderers, according to what is written in the Book of the Law of Moses, where the LORD commanded, "Fathers shall not be put to death because of their children, nor shall children be put to death because of their fathers. But each one shall die for his own sin." (2 Kings 14:6 citing Deuteronomy 24:16)
6. And I will not cause the feet of Israel to wander anymore out of the land that I gave to their fathers, if only they will be careful to do according to all that I have commanded them, and according to all the Law that my servant Moses commanded them." (2 Kings 21:8)
7. But he did not put their children to death, according to what is written in the Law, in the Book of Moses, where the LORD commanded, "Fathers shall not die because of their children, nor children die because of their fathers, but each one shall die for his own sin." (2 Chronicles 25:4 citing Deuteronomy 24:16)
8. And they set the priests in their divisions and the Levites in their divisions, for the service of God at Jerusalem, as it is written in the Book of Moses. (Ezra 6:18)
9. And all the people gathered as one man into the square before the Water Gate. And they told Ezra the scribe to bring the Book of the Law of Moses that the LORD had commanded Israel. (Nehemiah 8:1)
10. On that day they read from the Book of Moses in the hearing of the people. (Nehemiah 13:1)
11. All Israel has transgressed your law and turned aside, refusing to obey your voice. And the curse and oath that are written in the Law of Moses the servant of God have been poured out upon us, because we have sinned against him. He has confirmed his words, which he spoke against us and against our rulers who ruled us, by bringing upon us a great calamity. For under the whole heaven there has not been done anything like what has been done against Jerusalem. As it is written in the Law of Moses, all this calamity has come upon us; yet we have not entreated the favor of the LORD our God, turning from our iniquities and gaining insight by your truth. (Daniel 9:11-13)

New Testament

Jesus

1. And Jesus said to him, "See that you say nothing to anyone, but go, show yourself to the priest and offer the gift that Moses commanded, for a proof to them." (Matthew 8:4 citing Leviticus 14)
2. They said to him, "Why then did Moses command one to give a certificate of divorce and to send her away?" He said to them, "Because of your hardness of heart Moses allowed you to divorce your wives, but from the beginning it was not so." (Matthew 19:7-8 discussing Deuteronomy 24)
3. For Moses said, "Honor your father and your mother"; and, "Whoever reviles father or mother must surely die." (Mark 7:10 citing Exodus 20:12 and 21:17)
4. And as for the dead being raised, have you not read in the book of Moses, in the passage about the bush, how God spoke to him, saying, "I am the God of Abraham, and the God of Isaac, and the God of Jacob"? (Mark 12:26 citing Exodus 3:6)
5. "He said to him, 'If they do not hear Moses and the Prophets, neither will they be convinced if someone should rise from the dead.'" (Luke 16:31)
6. Then he said to them, "These are my words that I spoke to you while I was still with you, that everything written about me in the Law of Moses and the Prophets and the Psalms must be fulfilled." (Luke 22:44)
7. "For if you believed Moses, you would believe me; for he wrote of me. But if you do not believe his writings, how will you believe my words?" (John 5:46-47)
8. "Has not Moses given you the law? Yet none of you keeps the law. Why do you seek to kill me?" (John 7:19)

Others

1. And beginning with Moses and all the Prophets, he interpreted to them in all the Scriptures the things concerning himself. (Luke 24:27, Luke)
2. For the law was given through Moses; grace and truth came through Jesus Christ. (John 1:17, John)
3. "This man never ceases to speak words against this holy place and the law, for we have heard him say that this Jesus of Nazareth will destroy this place and will change the customs that Moses delivered to us." (Acts 6:13-14, Jews)
4. "Let it be known to you therefore, brothers, that through this man forgiveness of sins is proclaimed to you, and by him everyone who believes is freed from everything from which you could not be freed by the law of Moses." (Acts 13:39, Paul)
5. But some believers who belonged to the party of the Pharisees rose up and said, "It is necessary to circumcise them and to order them to keep the law of Moses." (Acts 15:5, Jewish Christians)
6. For it is written in the Law of Moses, "You shall not muzzle an ox when it treads out the grain." Is it for oxen that God is concerned? (1 Corinthians 9:9, Paul citing Deuteronomy 25:4)
7. Yes, to this day whenever Moses is read a veil lies over their hearts. (2 Corinthians 3:15, Paul)
8. Anyone who has set aside the law of Moses dies without mercy on the evidence of two or three witnesses. (Hebrews 10:28, Author of Hebrews citing Deuteronomy 17:6)