"darkness. Chaff like a cloud will be borne away on the wind, even from places where we see only floors of rich wheat. All who assume the ornaments of the sanctuary, but are not clothed with Christ's righteousness, will appear in the shame of their own nakedness. 5T 81.1"
"Whose fan is in his hand, and he will throughly purge his floor, and gather his wheat into the garner; but he will burn up the chaff with unquenchable fire."
Both passages use the imagery of chaff being separated from wheat to represent the separation of the wicked from the righteous.
"When trees without fruit are cut down as cumberers of the ground, when multitudes of false brethren are distinguished from the true, then the hidden ones will be revealed to view, and with hosannas range under the banner of Christ. Those who have been timid and self-distrustful will declare themselves openly for Christ and His truth. The most weak and hesitating in the church will be as David—willing to do and dare. The deeper the night for God's people, the more brilliant the stars. Satan will sorely harass the faithful; but, in the name of Jesus, they will come off more than conquerors. Then will the church of Christ appear “fair as the moon, clear as the sun, and terrible as an army with banners.” 5T 81.2"
"Every tree that bringeth not forth good fruit is hewn down, and cast into the fire."
Both passages discuss the cutting down of unfruitful trees, representing the judgment of those who do not bear good fruit.