וּבַשָּׁנָה֙ הָרְבִיעִ֔ת יִהְיֶ֖ה כָּל־פִּרְי֑וֹ קֹ֥דֶשׁ הִלּוּלִ֖ים לַיהוָֽה׃
And in the fourth year all the fruit thereof shall be holy, for giving praise unto the LORD.
Read kabbalistic (mystical) interpretation of Leviticus 19:24: and classical mystical sources.