One Scripture text (1 Chron. xxi. 25) says, "So David gave to Ornan for the place six hundred shekels of gold
by weight." And another Scripture (2 Sam. xxiv. 24) says, "So David bought the threshing-floor and the oxen for fifty shekels of silver." How is this? David took from each tribe fifty shekels, and they made together the total six hundred, i. e., he took silver to the value of fifty shekels of gold.
Zevachim, fol. 116, col. 2.
Rabbi Samlai explains that six hundred and thirteen commandments were communicated to Moses; three hundred and sixty-five negative, according to the number of days in the year, and two hundred and forty-eight positive, according to the number of members in the human body. Rav Hamnunah asked what was the Scripture proof for this. The reply was (Deut. xxxiii. 4), "Moses commanded us a law" (Torah), which by Gematria answers to six hundred and eleven. "I am," and "Thou shalt have no other," which we heard from the Almighty Himself, together make up six hundred and thirteen.
Maccoth, fol. 23, col. 2.
David, we are told, reduced these commandments here reckoned at six hundred and thirteen, to eleven, and Isaiah still further to six, and then afterward to two. "Thus saith the Eternal, Observe justice and act righteously, for my salvation is near." Finally came Habakkuk, and he reduced the number to one all-comprehensive precept (chap. ii. 4), "The just shall live by faith." (See Maccoth, fol. 24, col. 1.)
The precept concerning fringes is as weighty as all the other precepts put together; for it is written, says Rashi (Num. xv. 39), "And remember all the commandments of the Lord." Now the numerical value of the word "fringes" is six hundred, and this with eight threads and five knots makes six hundred and thirteen.
Shevuoth, fol. 29, col. 1.