From the wall of the city a thousand cubits It appears, by comparing these two verses together, that there were three thousand cubits allowed them from the wall of the city; the first thousand, properly called the suburbs, probably for outhouses, gardens, vineyards, and olive-yards; and the other two for pasturage, which are therefore called the field of the suburbs, (Leviticus 25:34,) by way of distinction from the suburbs themselves.
Related Commentaries of Numbers 35:4
Numbers 35:4-5
4 And the suburbs of the cities, which ye shall give unto the Levites, shall reach from the wall of the city and outward a thousand cubits round about.
5 And ye shall measure from without the city on the east side two thousand cubits, and on the south side two thousand cubits, and on the west side two thousand cubits, and on the north side two thousand cubits; and the city shall be in the midst: this shall be to them the suburbs of the cities.