Exodus 28:10

28:10 six ¹  of their names on one stone, and the six remaining names on the second stone, according to the order of their birth. ² 

Exodus 28:21

28:21 The stones are to be for the names of the sons of Israel, twelve, according to the number of ³  their names. Each name according to the twelve tribes is to be like ⁴  the engravings of a seal.

[28:10]  ¹ tn This is in apposition to the direct object of the verb “engrave.” It further defines how the names were to be engraved – six on one and the other six on the other.

[28:10]  ² tn Heb “according to their begettings” (the major word in the book of Genesis). What is meant is that the names would be listed in the order of their ages.

[28:21]  ³ tn For clarity the words “the number of” have been supplied.

[28:21]  ⁴ tn The phrase translated “the engravings of a seal” is an adverbial accusative of manner here.