“But we know that [to] the [ones] loving God all things work together for good, [to] those being called according to purpose” (Romans 8:28).
“Everyone practicing sin also practices lawlessness, and sin is lawlessness” (1 John 3:4).
“They went out from us, but they were not of us. For if they were of us, they would have remained with us; but [they left] so that it might be revealed that they all are not of us” (1 John 2:19).
“For also heresies need to be among you, so that the approved ones may become revealed among you” (1 Corinthians 11:19).
True Christians LAMENT heresies that sprout up among them (cf. Acts 20:28-31). They lament these heresies as violations and transgressions of God’s precepts (cf. 2 John 9-11), but they also LAUD and THANK God for actively causing them. Obviously, true Christians do NOT LAUD damnable transgressions of God’s law; they do NOT rejoice in unrighteousness (1 Corinthians 13:6). But they DO LAUD and THANK God for causing the heresy as it confirms the approved (regenerate) ones and exposes the disapproved unregenerate hypocrites and pretenders (1 Corinthians 11:19). The Scriptures teach us to thank God for everything, which includes His active causation of sin, both for our good and His glory.
Here is what Marc D. Carpenter preached concerning the need for heresies and our thanking God for them (certainly, it can be extremely bitter-sweet if a formerly dear brother or sister goes out from among us; cf. 1 John 2:19):
“Do you see what that’s saying? Heresies are NEEDED. There MUST be heresies. They are for the GOOD of God’s people. How can heresies be for the good of God’s people? Well, I first need to say that this is not talking about the heresies OF God’s people. This is talking about the heresies that come up AMONG those who profess to believe the gospel. Now just think of a group of people who profess to believe the gospel, and some of them truly believe the gospel, and some of them to NOT truly believe the gospel. But at the moment, since all profess to believe the gospel, they are all in fellowship with one another. Now we have already seen that some can fall away by troubles or persecution, and some can fall away by riches or lust. But what is one of the MAIN ways that people fall away? It is from HERESIES. So why is it a good thing that heresies come up among a group of professing believers? Well, it serves to WEED OUT the ones who don’t truly believe the gospel! It serves to show who is a true believer and who is NOT a true believer. As this passage says, ‘so that the approved ones may become revealed among you.’ Heresies come along in order to weed out the unbelievers and to reveal the true believers! When’s the last time you thanked God for heresies? Yet heresies are a GOOD thing when they DECREASE the number of people in a certain fellowship to the true believers! We’ve experienced this many times, too, haven’t we? We’re fellowshipping with certain people, and some heresy comes up, and those who are unbelievers are carried off by that heresy, while others stand firm, showing who among us is approved, which is another showing of God’s grace towards the vessels of mercy” (http://www.outsidethecamp.org/romans79.htm ).
This is an excerpt from a sermon on Romans 9:23a. An edifying, comforting, and educational sermon.
“And do not be drunk with wine, in which is debauchery, but be filled by the Spirit, speaking to yourselves in psalms and hymns and spiritual songs, singing and praising in your heart to the Lord, giving thanks at all times for all things in the name of our Lord Jesus Christ, even to God [the] Father” (Ephesians 5:18-20).