'Grass' is natural truth, and 'flower of the field' is spiritual truth, as in Isaiah 40:5, 6. Green grass, in the Word, signifies the good and truth of the church, and of faith, which first springs up in the natural man. This is also signified by 'herb in the field.' Grass and the pulse of the herb, as in Psalm 32:2, signify what is most vile. Grass signifies science from a spiritual origin, or that by which spiritual truth is confirmed. 'Reeds and rushes' signify science from a sensory origin, or the things which confirm the fallacies of the senses, as in Isaiah 25:7. This science, considered in itself, is only a part of the lowest natural degree, which may be justly called material and bodily, in which there is little or no life. Green grass also signifies that which is alive with man. 'Grass burnt up' signifies the things which are dead in him. Grass signifies the scientific principle. Just as green grass serves animals for support, spiritual truth serves men for spiritual nourishment.

(References: Apocalypse Explained 507)

2118. The expression 'Last Judgement' is used to mean the final period of a Church, and also to mean the final phase of each person's life. As regards the final period of a Church, the Last Judgement of the Most Ancient Church, which had existed before the Flood, occurred when their descendants perished, whose destruction is described by the Flood. The Last Judgement of the Ancient Church, which existed after the Flood, took place when almost all who belonged to that Church had become idolaters and had been scattered. The Last Judgement of the representative Church, which followed next, among the descendants of Jacob, came about when the ten tribes were led away into captivity and dispersed among the gentile nations; and later on when the Jews after the Lord's Coming were expelled from the land of Canaan and were scattered throughout the whole world. The Last Judgement of the Church existing at present, which is called the Christian Church, is what 'the new heaven and the new earth' is used to mean in John in the Book of Revelation.