Firstborn, in a supreme sense, represents the Lord as to divine celestial love, and also peope who were of the celestial church. The sanctification of the firstborn, as in Exodus 13, signifies faith in the Lord. The firstborn, in the spiritual sense of the Word, is good, for with infants the good of innocence is first infused by the Lord, by virtue of which man first becomes a man. Since good is of love, and man does not reflect upon his own love, but only upon the thoughts of his memory, and since good has not at first a quality, but acquires one when it is formed in truths, and without a quality nothing is perceived, hence it was unknown that good was the primary principle, or firstborn. Good is first conceived from the Lord in man, and is produced by truths, in which good is manifested, in its own form and effigy. Firstborn, as in Psalm 89:28, signifies the Lord's humanity.

6254. 'And I will bless them' means a foretelling regarding goodness and truth. This is clear from the meaning of 'blessing' as foretelling, as above in 6230, here a foretelling regarding goodness and truth, which are represented by 'Manasseh and Ephraim'. Being a very common word 'blessing' has various meanings. Included among them is the foretelling both of good things that are going to happen and also of bad ones, as is evident in the next chapter in which Israel foretold to his sons what was going to happen to them - bad things to some, such as Reuben, Simeon, and Levi, good ones to others, such as Judah and Joseph. That foretelling is called a blessing in Verse 28 of that chapter,

This is what their father spoke to them; and he blessed them, each according to his blessing he blessed them.

It is also clear from the words contained in the first verse of the chapter that 'blessing' means a foretelling,

Jacob called his sons, and said, Gather together, and I will tell you what will happen to you at the end of days.