This is Page 37 of the bound volume of The Deer's Cry at the Manx Museum.

"God's shield to protect me." I presume that the strongest part of a shield is at the centre where the boss" is and, therefore, in this illustration the centre of "GOD" is in the middle of the shield forming the boss, and instead of the "O" being heart shaped (see earlier pages) it is shield shaped.
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The words in the above paragraph are just my personal and subjective thoughts. Knox must have had so many ideas and thoughts behind this page and the other pages which, perhaps, we will never know.