הלכה על נדרים 121:1

From the laws of the commandment is that which they, may their memory be blessed, said (Mishneh Torah, Laws of Sabbatical Year and the Jubilee 10:16-17) that everything that is forbidden from work on the land in the seventh year is [also] forbidden on the Jubilee; and everything that is permitted on [the one] is permitted on [the other]. And the liability for one who does [forbidden work] is the same in both of them. The seventh [year] is more than the Jubilee in that it releases [loans], and specifically at its end. And the Jubilee is more than the seventh [year] in that it releases land and removes slaves at [its] beginning. And the Jubilee year does not count in the tally of the years of the seven-year cycle. Rather we count forty-nine years, which are seven times seven years; and after the sabbatical year, which is in the last seven-year cycle, we make the Jubilee in the fiftieth year; and we begin to tally for [the next] Jubilee in the fifty-first year. And it is [also] the beginning of the six years of the seven-year cycle (see Nedarim 61a).