Charles Spurgeon Commentary Leviticus 25:17-21

"And ye shall not wrong one another; but thou shalt fear thy God: for I am Jehovah your God. Wherefore ye shall do my statutes, and keep mine ordinances and do them; and ye shall dwell in the land in safety. And the land shall yield its fruit, and ye shall eat your fill, and dwell therein in safety. And if ye shall say, What shall we eat the seventh year? Behold, we shall not sow, nor gather in our increase; then I will command my blessing upon you in the sixth year, and it shall bring forth fruit for the three years." — Leviticus 25:17-21 (ASV)

Not merely for the one year of rest, but fruit for three years.