That the Pentateuch was written by Moses, is the voice of all antiquity. It has been all along, even to this day, the received opinion of both Jews and Christians, that Moses, being commanded and inspired by God, wrote those books, which are called the Pentateuch, except only some particular passages, which were inserted afterwards by a divine direction, for the better understanding of the history.
We read, Exodus xxiv. 4, 7, 8. that Moses wrote all the words of the Lord, which before that time had been delivered from mount Sinai, in a book, which is there called The Book of the Covenant. Afterwards, when God had added more precepts, he again commands Moses to write them, Exod. xxxiv. 27. “And the Lord said unto Moses, Write thou these words; for after the tenor of these words have I made a covenant with thee and with Israel.” Near 40 years afterwards, Moses was commanded to write all the commands which God had given the people, and the revelations which he had made of himself to them, in a book, to be laid up by the side of the ark of the covenant, to be kept for a testimony against Israel. Deut. xxxi. 24-26. “And it came to pass, when Moses had made an end of writing the words of this law in a book, until they were finished, that Moses commanded the Levites, which bare the ark of the covenant of the Lord, saying, Take this book of the law, and put it in the side of the ark of the covenant of the Lord your God, that it may be there for a witness against thee.” And the original of this book of the law was in being, as we read expressly, till the times of Josiah; 2 Kings xxii. and 2 Chron. xxxiv. and so, doubtless, till the captivity into Babylon. This book of the law, which Moses was thus commanded to lay up beside the ark, did not only comprehend those things, which were contained in some of those preceding chapters of Deuteronomy, wherein some things of the law were repealed; but the whole system of divine law, which God gave to the children of Israel, expressing the whole of the duty which God expected of them. This appears from Josh. i. 7, 8. “Only be thou strong and very courageous, that thou mayest observe and do according to all the law which Moses, my servant, commanded them; turn not from it to the right hand or to the left, that thou mayest prosper whithersoever thou goest. This book of the law shall not depart out of thy mouth, but thou shalt meditate on them day and night, that thou mayest observe to do according to all that is written therein,” &c. And therefore the Levites, whom Jehoshaphat sent to teach the people their duty, did not do it in any other way than out of the book of the law. 2 Chron. xvii. 9. “And they taught in Judah, and had the book of the law of the Lord with them, and went about, throughout all the cities of Judah, and taught the people.”
And then it is further evident, that the book of the law which we have an account of Moses’s committing to the Levites, to be laid up in the side of the ark, Deut. xxxi. did not contain merely what had then lately been delivered in some preceding chapters of Deuteronomy; because in this book of the law were contained the precepts concerning burnt-offerings and sacrifices, and the office and business of the priesthood; which are not contained so much in Deuteronomy as in Leviticus and Numbers, as appears from 2 Chron. xxiii. 18. “Also Jehoiada appointed the officers of the house of the Lord, by the hands of the priests, the Levites, whom David had distributed in the house of the Lord to offer the burnt-offering of the Lord, as it is written in the law of Moses.” 2 Chron. xxxv. 12. Neh. x. 34, 35, 36. Hag. ii. 11., &c. Josh. viii. 31. Ezra vi. 18. Neh. viii. 14, 15. 2 Chron. xxx. 5. and xxxi. 3. And in the book of the law were contained not merely the precepts which God delivered to Moses, but the sanctions and enforcements of those laws, the promises and threatenings; as appears from Deut. xxix. 20, 21. “The Lord will not spare him, but then the anger of the Lord, and his jealousy, shall smoke against that man, and all the curses that are written in this book shall lie upon him; and the Lord shall blot out his name from under heaven; and the Lord shall separate him unto evil, out of all the tribes of Israel, according to all the curses of the covenant, that are written in this book of the law. See also ver. 27. and Deut. xxviii. 61. “Also every plague, and every sickness, which is not written in the book of this law, will the Lord bring upon thee, until thou be destroyed.” See also 2 Kings xxii. 13, 16, 19. and parallel places in 2 Chron. xxxiv. Dan. ix. and Josh. viii. 34, 35. “And afterwards he read all the words of the law, the blessings and the cursings according to all that is written in the book of the law. There was not a word, of all that Moses commanded, that Joshua read not.” See Psal. cv. 8, 9, 10. And not only the promises and threatenings were contained in the book of the law, but all the revelations which God gave, which tended to enforce it, or which in any way related to it, and even the prophecies that were there contained of what should afterwards happen to the people on their sin or on their repentance. This appears from Neh. i. 8, 9. “Remember, I beseech thee, the word that thou commandest thy servant Moses, saying, If ye transgress, I will scatter you abroad among the nations. But if ye turn unto me, and keep my commandments, and do them, though there were of you cast out unto the uttermost part of the heaven, yet will I gather them from thence, and will bring them unto the place that I have chosen to set my name there.”