I am certainly questioning the faith of others based on the fruit they bear.
By the authority of Lord Jesus, and His Apostles, I have every right to do so, so that they may come to an accurate knowledge of the faith and so be saved.
Matthew 7:15-22 (NIV)
15 “Watch out for false prophets. They come to you in sheep’s clothing, but inwardly they are ferocious wolves. 16 By their fruit you will recognize them. Do people pick grapes from thornbushes, or figs from thistles? 17 Likewise, every good tree bears good fruit, but a bad tree bears bad fruit. 18 A good tree cannot bear bad fruit, and a bad tree cannot bear good fruit. 19 Every tree that does not bear good fruit is cut down and thrown into the fire. 20 Thus, by their fruit you will recognize them.
21 “Not everyone who says to me, ‘Lord, Lord,’ will enter the kingdom of heaven, but only the one who does the will of my Father who is in heaven.
Galatians 5:19-25 (NIV)
19 The acts of the flesh are obvious: sexual immorality, impurity and debauchery; 20 idolatry and witchcraft; hatred, discord, jealousy, fits of rage, selfish ambition, dissensions, factions 21 and envy; drunkenness, orgies, and the like. I warn you, as I did before, that those who live like this will not inherit the kingdom of God.
2 Thessalonians 3:10-15 (NIV)
10 For even when we were with you, we gave you this rule: “The one who is unwilling to work shall not eat.”
11 We hear that some among you are idle and disruptive. They are not busy; they are busybodies. 12 Such people we command and urge in the Lord Jesus Christ to settle down and earn the food they eat. 13 And as for you, brothers and sisters, never tire of doing what is good.
14 Take special note of anyone who does not obey our instruction in this letter. Do not associate with them, in order that they may feel ashamed. 15 Yet do not regard them as an enemy, but warn them as you would a fellow believer.