John Calvin on Leviticus 19:23-26

23. And when ye shall come. There seems to me no question but that the circumcision of trees as well as of men appertains to the First Commandment, not only that the Jews might see a symbol of their own adoption in the very trees, but that they might learn that it was permitted to none but the children of God to feed on their fruit; and also that whatsoever the earth produces is in a manner profane, until it is purified. For surely by this ceremony was set forth what Paul teaches, that all things are “sanctified by the word of God, and prayer,” (1 Timothy 4:5;) not that anything is in itself impure, but because the earth has contracted pollution from the corruption of man, it is just, as regards us, that the harmless fruits also should be accounted to be in uncircumcision. In sum, God would raise up a wall whereby He might separate His people from the Gentiles, and at the same time admonish them that a legitimate use of those things which the earth produced could not be made by the sons of Adam, except by special privilege. But the similitude of uncircumcision, until the year appointed for their being circumcised, was a very appropriate one, that they might acknowledge the fruits of their trees to be pure for them by the same right whereby they were consecrated as God’s peculiar people. But, lest the three years’ unproductiveness should press heavily upon them, he promises them compensation from the future blessing of God; for, if they should abstain from eating the unclean fruit, a larger produce was to be expected in future.