From his The Truth of the Christian Religion, Hugo Grotius (1583-1645), Remonstrant and founder of International Treaty Law, offers an answer to the question why God permits differences and errors to arise among Christians. Grotius writes the following.
Perhaps some may here object against what has been said, that the Divine Providence would have better consulted the preservation of the Christian doctrine if it had prevented the errors that are and have been amongst the Christians, and maintained truth and constant agreement, which is the companion of it, amongst them, by its omnipotence.
But it is not for us to instruct God how He ought to direct Himself in the government of human affairs, that they might be better. On the contrary, it is our duty to think that God had very wise reasons for suffering what He did suffer, though we cannot so much as guess at what they are. But if any probable reasons can be given for the things that are done, we ought to believe that God permits those things which daily come to pass to be done for these or more weighty reasons.
To make a conjecture from the reason of things, we are above all things sure that the design of God was to create men free, and to suffer them to continue to the end: that is, not so good that they must necessarily continue good always, nor so bad as that they must of necessity always submit to vice; but mutable, so as that they might pass from vice to virtue, and again from virtue to vice; and this with more or less ease, according as they had a longer or shorter time given up themselves to virtue or vice.
Such we see the Hebrew people of old were and such were the Christians afterwards. Neither of them were drawn by an irresistible force either to virtue or vice, but only restrained by laws, which proposed reward to the good and punishment to the bad; to which were added by the divine providence various incitements to virtue, and discouragements from vice, but yet neither of them deprived man of his native liberty, whereby he had a power of obeying or disobeying God, as is evident from experience; for there were always good and bad, though the divine laws prescribed virtue, and prohibited vice equally to all.
That this would be so amongst Christians, Christ has plainly signified in two parables, the one of the tares which the enemy sowed after the wheat was sown; the other of the net which took good and bad fish alike; by which He signified that there would always be in the church a mixture of good and bad Christians; whence it follows that He very well saw the evils that would always be in the Christian church.
Moreover Paul tells the Christians that there must be [divisions] amongst Christians, that they who are approved may be made manifest [1 Cor. 11:19]. And indeed unless there had been differences among Christians concerning doctrine, there had been no room left for choice, and for that sort of virtue, by which truth is preferred to all other things.
Therefore even in this particular also, the divine wisdom shines bright; which caused an excellent virtue to flourish out of the midst of the vices of men. If any one should object here, as some do, that it were better there were no such kind of virtue than that there should be vices contrary to it, whence so many horrid crimes, so many calamities, and so great miseries should befall mankind, and such heavy punishment attend them after this life, to this we answer that these evils are not of such a consideration with God that upon their account He should not give an instance of His power in creating free agents.
Unless this had been done, no creature would have believed that it could have been done. Nay, God Himself would not have been thought to be free unless He Himself had planted this opinion of Himself by His omnipotence in the minds of men, which otherwise they never could have conceived from His works.
Nor could He have been worshiped, if He had been thought to do, or to have done all things, not out of His free goodness, but by a certain fatal necessity; unless by a fatal worship also, and such an one as is not at all free. The vices and calamities of this or the other life are not comparable to so great an evil as the supposing God to be ignorant of any thing; for if we find any difficulty about them, we ought to consider that God is most good, just, powerful, and wise, and will not act otherwise than agreeable to His perfections; and will easily find a way and go in it, whereby to clear those things which seem to us to be entangled; and to show to all intelligent creatures that nothing was done by Him which ought not to have been done.
In the mean time, till that day spring, in which all the clouds of our ignorance shall be dispersed, He hath given us such experience of Himself, and such instances of His perfections, on the account of which we may and ought entirely to confide in Him, and patiently to wait for what He will have come to pass. . . .
Hugo Grotius, The Truth of the Christian Religion, trans. John Clarke (La Vergne: Kessinger Publishing, 2010), 272-75.