D&C 101

 Those who believe that we are saved by grace just by confessing belief in Jesus Christ.  There is more required.  To the saints in Missouri, the Lord taught - 

"...in consequence of their transgressions;

3 Yet I will own them, and they shall be mine in that day when I shall come to make up my jewels.

4 Therefore, they must needs be chastened and tried, even as Abraham, who was commanded to offer up his only son.

5 For all those who will not endure chastening, but deny me, cannot be sanctified.

6 Behold, I say unto you, there were jarrings, and contentions, and envyings, and strifes, and lustful and covetous desires among them; therefore by these things they polluted their inheritances.

7 They were slow to hearken unto the voice of the Lord their God; therefore, the Lord their God is slow to hearken unto their prayers, to answer them in the day of their trouble.

8 In the day of their peace they esteemed lightly my counsel; but, in the day of their trouble, of necessity they feel after me."  (Doctrine and Covenants 101:2–8)

But if they truly repent - 

"...I will remember mercy."  (Doctrine and Covenants 101:9)