In this quotation Franklin is summarizing his beliefs about marriage, which several scholars have argued he bases on his own close reading of several Biblical Proverbs.
For example, we can see the sentiments of "Good wives usually make good husbands," in Proverbs 31:10-31, where the Bible states that a virtuous woman is more valuable than rubies because she will be trustworthy, active, modest and possess self-discipline, generosity, a charitable heart.
In Proverbs 18:22, the Old Testament also states that finding such a wife is a blessing from the Lord, and in Proverbs 12:4 it states that a good wife is a crown for her husband, meaning that she is something he can be proud to be joined with as a King can feel deep pleasure in his reign.
Conversely, the Proverbs of the Bible state that a disgraceful woman is like cancer in her husband's bones, always eating away at his mental, emotional, physical, financial, and spiritual resources. This negation also supports the statement Franklin seems to be making, which is that a good wife can be defined by how she contributes to her husband's success (remember this was an era when women's roles were much different than they are today).
This close examination of the scriptures in comparison with the quotation can be coupled with Franklin's own autobiography, which shows although he did not conform to the traditional Christian faith, he was raised as a Puritan, lived as a Deist and embraced a firm and unmovable faith in God and His works, to prove this point. Franklin had a keep skepticism about life and is known as the "questioning Christian" today, but many of his secular ideas had their foundation in the scriptures.