"The influence most to be feared by the church is not that of open opposers, infidels, and blasphemers, but of inconsistent professors of Christ. These are the ones who keep back the blessing of the God of Israel and bring weakness upon the church, a reproach that is not easily wiped away. While Joshua was lying on his face upon the ground, pouring out his soul to God with agony of spirit and with tears, God's command was a reproof: “Get thee up; wherefore liest thou thus upon thy face?” 4T 493.1"
"Beware of false prophets, which come to you in sheep’s clothing, but inwardly they are ravening wolves."
EGW directly quotes God's command to Joshua from the Achan narrative, and connects it to the idea that internal corruption is more dangerous than external opposition.
"The popular churches are filled with men who, while they make a pretense of serving God, are thieves, murderers, adulterers, and fornicators; but those who profess our lowly faith claim a higher standard. They should be Bible Christians, and they must be diligent in the study of the Chart of life. Carefully and prayerfully should they examine the motives which prompt them to action. Those who would put their trust in Christ should begin to study the beauties of the cross now. If they would be living Christians they must begin to fear and obey God now. If they will they can save their souls from ruin and make a success of winning eternal life. 4T 493.2"
"Know ye not that the unrighteous shall not inherit the kingdom of God? Be not deceived: neither fornicators, nor idolaters, nor adulterers, nor effeminate, nor abusers of themselves with mankind, Nor thieves, nor covetous, nor drunkards, nor revilers, nor extortioners, shall inherit the kingdom of God."
EGW's passage echoes the sentiment and lists similar sins as 1 Corinthians 6:9-10, emphasizing that those who practice such things will not inherit the kingdom of God.