Doctrine and Covenants 52:17-18

17 And again, he that trembleth under my power shall be made strong, and shall bring forth fruits of praise and wisdom, according to the revelations and truths which I have given you.

18 And again, he that is overcome and bringeth not forth fruits, even according to this pattern, is not of me.

Matthew 7:15-20

15 ¶ Beware of false prophets, which come to you in sheep’s clothing, but inwardly they are ravening wolves.

16 Ye shall know them by their fruits. Do men gather grapes of thorns, or figs of thistles?

17 Even so every good tree bringeth forth good fruit; but a corrupt tree bringeth forth evil fruit.

18 A good tree cannot bring forth evil fruit, neither can a corrupt tree bring forth good fruit.

19 Every tree that bringeth not forth good fruit is hewn down, and cast into the fire.

20 Wherefore by their fruits ye shall know them.