John Calvin writes,
“Accordingly, inasmuch as it was of importance to us to recognise it, the Lord has distinguished it by certain marks, and as it were symbols. It is, indeed, the special prerogative of God to know those who are his, as Paul declares in the passage already quoted (2 Tim. 2:19). And doubtless it has been so provided as a check on human rashness, the experience of every day reminding us how far his secret judgments surpass our apprehension. For even those who seemed most abandoned, and who had been completely despaired of, are by his goodness recalled to life, while those who seemed most stable often fall. Hence, as Augustine says, “In regard to the secret predestination of God, there are very many sheep without, and very many wolves within” (August. Hom. in Joan. 45). For he knows, and has his mark on those who know neither him nor themselves.” (Institutes of the Christian Religion, IV.I.VIII)
Beautiful. Yes, said by an Arminian :).