The sabbatical year and the year of Jubilee belong to that great sabbatical system which runs through the religious observances of the Law, but rest upon moral rather than upon formally religious ground. It is not, therefore, without reason that they are here set apart from the set times which fell strictly within the sphere of religious observances.

And the Lord spake unto Moses in Mount Sinai,.... Not when Moses was with the Lord on that mount forty days, but after he came down from thence, even after the tabernacle was set up, while the children of Israel where encamped about that mountain, and before they took their journey from thence; for they continued some time in the wilderness of Sinai, and here it was the Lord spoke to Moses; for the words may be rendered "by" or "near Mount Sinai" (g); and so Josephus (h) says, the following laws were delivered to Moses, when Israel was encamped under Mount Sinai:
saying; as follows.
(g) "apud seu juxta montem", Piscator; so Ainsworth, Patrick, &c. (h) Antiqu. l. 3. c. 12. sect. 3.

All labour was to cease in the seventh year, as much as daily labour on the seventh day. These statues tell us to beware of covetousness, for a man's life consists not in the abundance of his possessions. We are to exercise willing dependence on God's providence for our support; to consider ourselves the Lord's tenants or stewards, and to use our possessions accordingly. This year of rest typified the spiritual rest which all believers enter into through Christ. Through Him we are eased of the burden of wordly care and labour, both being sanctified and sweetened to us; and we are enabled and encouraged to live by faith.

The law for the sabbatical and jubilee years brings to a close the laws given to Moses by Jehovah upon Mount Sinai. This is shown by the words of the heading (Leviticus 25:1), which point back to Exodus 34:32, and bind together into an inward unity the whole round of laws that Moses received from God upon the mountain, and then gradually announced to the people. The same words are repeated, not only in Leviticus 7:38 at the close of the laws of sacrifice, but also at Leviticus 26:46, at the close of the promises and threats which follow the law for the sabbatical and jubilee years, and lastly, at Leviticus 27:34, after the supplementary law concerning vows. The institution of the jubilee years corresponds to the institution of the day of atonement (ch. 16). Just as all the sins and uncleannesses of the whole congregation, which had remained unatoned for and uncleansed in the course of the year, were to be wiped away by the all-embracing expiation of the yearly recurring day of atonement, and an undisturbed relation to be restored between Jehovah and His people; so, by the appointment of the year of jubilee, the disturbance and confusion of the divinely appointed relations, which had been introduced in the course of time through the inconstancy of all human or earthly things, were to be removed by the appointment of the year of jubilee, and the kingdom of Israel to be brought back to its original condition. The next chapter (ch. 26) bears the same relation to the giving of the law upon Sinai as Exodus 23:20-33 to the covenant rights in Ex 20:22-23:19.

In mount Sinai - That is, near mount Sinai. So the Hebrew particle beth is sometimes used. So there is no need to disturb the history in this place.