וְצִוִּ֤יתִי אֶת־בִּרְכָתִי֙ לָכֶ֔ם בַּשָּׁנָ֖ה הַשִּׁשִּׁ֑ית וְעָשָׂת֙ אֶת־הַתְּבוּאָ֔ה לִשְׁלֹ֖שׁ הַשָּׁנִֽים׃
then I will command My blessing upon you in the sixth year, and it shall bring forth produce for the three years.
Read kabbalistic (mystical) interpretation of Leviticus 25:21: and classical mystical sources.