I do not think it necessary for salvation to know Christ according to the flesh : but with regard to the Eternal Son of God, that is the Eternal Wisdom of God, which has manifested itself in all things and especially in the human mind, and above all in Christ Jesus, the case is far otherwise. For without this no one can come to a state of blessedness, inasmuch as it alone teaches, what is true or false, good or evil. And, inasmuch as this wisdom was made especially manifest through Jesus Christ, as I have said, his disciples preached it, in so far as it was revealed to them through him, and thus showed that they could rejoice in that spirit of Christ more than the rest of mankind. The doctrines added by certain churches, such as that God took upon himself human nature, I have expressly said that I do not understand; in fact, to speak the truth, they seem to me no less absurd than would a statement, that a circle had taken upon itself the nature of a square. This I think will be sufficient explanation of my opinions concerning the three points mentioned. Whether it will be satisfactory to Christians you will know better than I.
• Variant translation: The eternal wisdom of God … has shown itself forth in all things, but chiefly in the mind of man, and most of all in Jesus Christ.

What It Means

This is a placeholder explanation generated by the low-overhead model. It interprets "I do not think it necessary for salvation to know Christ according to the flesh : but with regard to the Eternal Son of God, that is the Eternal Wisdom of God, which has manifested itself in all things and especially in the human mind, and above all in Christ Jesus, the case is far otherwise. For without this no one can come to a state of blessedness, inasmuch as it alone teaches, what is true or false, good or evil. And, inasmuch as this wisdom was made especially manifest through Jesus Christ, as I have said, his disciples preached it, in so far as it was revealed to them through him, and thus showed that they could rejoice in that spirit of Christ more than the rest of mankind. The doctrines added by certain churches, such as that God took upon himself human nature, I have expressly said that I do not understand; in fact, to speak the truth, they seem to me no less absurd than would a statement, that a circle had taken upon itself the nature of a square. This I think will be sufficient explanation of my opinions concerning the three points mentioned. Whether it will be satisfactory to Christians you will know better than I.
• Variant translation: The eternal wisdom of God … has shown itself forth in all things, but chiefly in the mind of man, and most of all in Jesus Christ." in the context of "Letter 21 (73) to Henry Oldenburg, November (1675)" to mean that wisdom is timeless.