Why do we have trials?

I found a new scripture while reading about the similitude between Abraham about to sacrifice Isaac with the Father sacrificing the Son (I'll post about that later).

This is a common question we ask, "Why do we have trials?" "Why must I go through something challenging AGAIN?" People always respond that it's to make us strong or to test us. Yeah, yeah... Well, I found a scripture that is absolutely amazing!! Doctrine and Covenants 136:31 reads,

My people must be ^atried in all things, that they may be prepared to receive the ^bglory that I have for them, even the glory of Zion; and he that will not ^cbear chastisement is not worthy of my kingdom.

If you follow the footnote of 'glory' is says to look in the topical guide under 'celestial glory'. In the bible dictionary there is "Glory of the Lord" which says,

Glory of the Lord, or of Jehovah. An expression that occurs frequently in the O.T. It sometimes denotes the fulness of the majesty of God, revealed in the world and made known to men (Num. 14:21–22; Isa. 6:3; 66:19); in other places it denotes some outward and visible manifestation of the Divine presence. 

What a very cool scripture, isn't it?