why would God damn all the souls that were weaker to temptation and bless all the souls which were resistant?

The answer to this question appears throughout the bible and is most explicitly stated in the following verse:

1 Corinthians 10:13b ...And God is faithful; he will not let you be tempted beyond what you can bear. But when you are tempted, he will also provide a way out so that you can stand up under it.

God only allows temptations appropriate to an individual's ability to deal with them.