Hundred
It's a landmark for a young child to count to 100; it sort of covers all the "ordinary" numbers. One hundred is obviously significant for other groupings: 100 cents is a dollar; 100 yards is a touchdown; 100 years is a century, and the landmark for a very long life. It makes sense, then, that in the Bible, 100 represents fullness or a state of completion, or in some instances simply "much." For instance, people marvel that Abraham had Isaac when he was 100 years old; the number represents the point at which the Lord, when growing up as Jesus, united the human elements of himself with the divine elements and in a sense became "complete.
Arcana Coelestia #3514
3514. 'And I will bless you before Jehovah' means conjunction thereby. This is clear from the meaning of 'I will bless you' as an alliance to its own life, dealt with above in 3504. Here, because the words 'I will bless you before Jehovah' are used, conjunction is meant. The expression 'alliance' is used to refer to the communication of the truth of the natural with the good of the rational, but the expression 'conjunction' to refer to the communication of the good of the natural with the good of the rational. For a parallelism exists between God and man so far as celestial things, which are forms of good, are concerned, but not where spiritual things, which are forms of truth, are concerned, see 1832.