His servants cannot unite with them

"Here the temperance work, one of the most prominent and important of moral reforms, is often combined with the Sunday movement, and the advocates of the latter represent themselves as laboring to promote the highest interest in society; and those who refuse to unite with them are denounced as the enemies of temperance and reform. But the fact that a movement to establish error is connected with a work which is in itself good, is not an argument in favor of the error. We may disguise poison by mingling it with wholesome food, but we do not change its nature. On the contrary, it is rendered more dangerous, as it is more likely to be taken unawares. It is one of Satan's devices to combine with falsehood just enough truth to give it plausibility. The leaders of the Sunday movement may advocate reforms which the people need, principles which are in harmony with the Bible, yet while there is with these a requirement which is contrary to God's law, his servants cannot unite with them (in their cause). Nothing can justify them in setting aside the commandments of God for the precepts of men".

The Great Controversy, pp. 587-88.