And indeed, there must be differences among you to show which of you are approved.

Deuteronomy 13:3
you must not listen to the words of that prophet or dreamer. For the LORD your God is testing you to find out whether you love Him with all your heart and with all your soul.

Matthew 18:7
Woe to the world for the causes of sin. These stumbling blocks must come, but woe to the man through whom they come!

Luke 17:1
Jesus said to His disciples, "It is inevitable that stumbling blocks will come, but woe to the one through whom they come!

1 Corinthians 11:20
Now then, when you come together, it is not the Lord's Supper you eat.

2 Corinthians 12:20
For I am afraid that when I come, I may not find you as I wish, and you may not find me as you wish. I fear that there may be quarreling, jealousy, rage, rivalry, slander, gossip, arrogance, and disorder.

Galatians 5:20
idolatry and sorcery; hatred, discord, jealousy, and rage; rivalries, divisions, factions,

1 Timothy 4:1
Now the Spirit expressly states that in later times some will abandon the faith to follow deceitful spirits and the teachings of demons,

2 Peter 2:1
Now there were also false prophets among the people, just as there will be false teachers among you. They will secretly introduce destructive heresies, even denying the Master who bought them--bringing swift destruction on themselves.

1 John 2:19
They went out from us, but they did not belong to us. For if they had belonged to us, they would have remained with us. But their departure made it clear that none of them belonged to us.

For there must be also heresies among you, that they which are approved may be made manifest among you.