Some years after, he imagined that the shortest way to a coalition of Christians would be to reduce the articles of faith to a small number.  “It were well, says he[656], if Christians would reflect how few the points are, and how clearly expressed in Scripture, which constitute the Rule of Faith laid down by St. Irenaeus and Tertullian; and as it is not allowed to doubt of these, the liberty left to men in others might contribute to the peace of the Church.”

Afterwards he went much farther.  “I could wish, he says to his brother[657], Nov. 14. 1643, that Utengobard, when his health will permit, would write something, if he has not done it already, on the necessity of restoring the unity of the Church; and by what means it may be done.  Many think that the true way would be to distinguish between what is necessary, and what is not; and to leave men at full liberty in the latter:  but it is as difficult to know what is necessary, as to know what is true.  The Scriptures, they say, are the rule:  but interpreters vary on the passages referred to.  I know not, therefore, whether it would not be best to adhere to the sentiments of the Catholic Church concerning faith and good works:  for I think they hold all that is necessary to be believed in order to salvation.  As to other articles which have been determined by Councils, or received by the first Christians, we must adopt the moderate interpretation, and such we shall find on every point.  If any one cannot prevail with himself to be silent in relation to things, of which he has no certainty, but will disturb the unity of the Church, instead of labouring to restore it, matters will proceed from bad to worse.”

Sometimes Grotius imagined he should succeed.  Nov. 23, 1641, he writes to Gerard Vossius[658], that Codurus, Justellus, and Melitiere, three of the most learned Protestants, had thanked him for what he had written on the Consultation of Cassander.  “I perceive, says he to his brother, by conversing with the men of most learning among the Reformed, and explaining my sentiments to them, that they are of my opinion:  their number will increase if my treatises are dispersed; in which, I can truly affirm, I have said nothing from a party spirit, but followed truth as closely as I could.”

He writes to his father[659], that he was not without hopes of some good effect from his incessant labours to restore peace to Christendom.  “That day will at length shine forth, of which we now perceive the dawn:  for many great, pious, and learned men, of both parties, begin to see how unreasonable it is to neglect the reformation of manners while we are framing new tenets, and censuring old ones, which require only a good comment.  This excellent design I recommend to your prayers; it was you gave me the first hint of it.”

He writes to his brother[660], June 15, 1641, “I have received a visit from some Catholic Counsellors of State, and Codurus the clergyman, who expect the coalition will quickly take place, and pay great regard to my opinion.  May the God of peace direct the whole to the advancement of truth and piety.”