In Revelation 19:12, this symbolically means that what the Word is like in its spiritual and celestial senses, no one sees but the Lord, and the person to whom He reveals it. (Apocalypse Revealed 824)

824. He had a name written that no one knew but Himself. This symbolically means that what the Word is like in its spiritual and celestial senses, no one sees but the Lord, and the person to whom He reveals it.

A name symbolizes someone's character (no. 165 and elsewhere), here the character of the Word, or what the Word is like inwardly, that is, in its spiritual and celestial senses. It is said to be a name written, because the Word exists both among people on earth and among angels in heaven (see The Doctrine of the New Jerusalem Regarding the Sacred Scripture, nos. 70-75.). No one's knowing the name but Himself means, symbolically, that no one but the Lord Himself sees it, that is, what the Word is like in its spiritual sense, and the person to whom He reveals it.

That no one sees the Word's spiritual meaning but the Lord alone, that no one accordingly sees that meaning unless enabled to do so by the Lord, and that no one is enabled to do so by the Lord unless he possesses Divine truths from the Lord, may be seen in The Doctrine of the New Jerusalem Regarding the Sacred Scripture 26.