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.

4297. 'And he blessed him there' means a joining to the Divine celestial-spiritual. This is clear from the meaning of 'blessing' as a joining together, dealt with in 3504, 3514, 3565, 3584, a joining to the Divine celestial-spiritual being meant here, as is clear from what has gone before concerning Jacob's being named Israel; for 'Israel' represents the Lord's Divine celestial-spiritual, 4286. What the celestial-spiritual is, see that same paragraph.