675. As regards the statement 'birds according to their kinds, beasts according to their kinds, and [every] creeping thing according to its kind' it should be recognized that with everybody countless genera and still more countless species exist of intellectual concepts and of desires of the will which are all quite distinct and separate from one another, though the individual is not conscious of it. In man's regeneration however the Lord draws out every single thing in its proper order, separating them all from one another and arranging them so that they may be turned in the direction of truths and goods and may be joined to them. And this takes place varyingly according to people's states, which are countless as well. Yet to all eternity all those things in man's will and understanding can never be totally perfected, for each genus, each species, and each state consists of elements which are limitless both individually and even more so when combined with others. Man does not even know about this, still less can he know in what way he is regenerated. This is what the Lord tells Nicodemus about man's regeneration, The spirit blows where it wills, and you hear the sound of it, but you do not know whence it comes or whither it goes; so it is with everyone who has been begotten of the spirit. John 3:8.

Fifty is also half of 100, which has a similar meaning; the Writings tell us that when used together with 100, fifty represents an intermediate state. God rested on the seventh day of creation. That represents a state of holiness and tranquility that was preserved in the form of the sabbath. Holier still was the seventh sabbath, which happened every 49 days. The Israelites would follow that solemn day with the “feast of the seven sabbaths” on the 50th day, and for similar reasons had a jubilee year every 50th year. For these reasons, among others, “fifty” in the Bible is the completion of a cycle, and in most cases represents fullness or sufficiency.