862. That 'it happened at the end of forty days' means the duration of the former state, and the beginning of the one that followed, is clear from the meaning of 'forty', see 730, where, the subject being temptation, the phrase 'forty days and forty nights' was used, which meant the duration of temptation. Here, since the subject is the state following temptation, 'forty days' is mentioned but not forty nights. The reason is that charity now starts to appear, which in the Word is compared to the day and is called the day. Faith however which precedes but has not yet been so joined to charity is compared to the night and is called the night, as in Genesis 1:16, and elsewhere in the Word. Faith is also called 'the night' in the Word because it receives its light from charity, just as the moon does from the sun. Faith is therefore also compared to the moon and is called the moon; and love or charity is compared to the sun and is called the sun. 'Forty days', or the duration of time meant by them, refers both to the things that precede and to those that follow; hence the statement 'at the end of forty days', which accordingly means both the duration of the previous state, and the beginning of the one being described now. This then begins the description of the second state following temptation of the member of this Church.

'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)