Parents perpetuate their liues in their posterity, and their masters in their imitation. Children do natureally rather follow the failings then the vertues of their predecessors, but I am perswaded better things of you. You once desired me to leaue something for you in writeing that you might look vpon when you should see me no more. I could think of nothing more fit for you, nor of more ease to my self, then these short meditations following. Such as they are I bequeath to you: small legacys are accepted by true friends, much more by duty sull children. I haue avoyded incroaching upon others conceptions, because I would leaue you nothing but myne owne, though in value they fall short of all in this kinde, yet I presume they will be better pris'd by you for the Authors sake, the Lord blesse you with grace heer, and crown you with glory heerafter, that I may meet you with rejoyceing at that great day of appearing, which is the continuall prayer, of your affectionate mother.
The letter (the image here is a facsimile of the original manuscript in Bradstreet's handwriting) was, in fact, a dedication to her book Meditations Divine and Morall. The book is comprised of a series of short affirmations and religious aphorisms, along with a few more practical recommendations for living. One, for example, is aimed at the mothers of young children (with, of course, the requisite moral):
A prudent mother will not clothe her little child with a long and cumbersome garment; she easily foresees what events it is like to produce—at the best but falls and bruises, or perhaps somewhat worse. Much more will the All-wise God proportion his dispensations according to the stature and strength of the person he bestows them on. Large endowments of honor, wealth, or a healthful body would quite overthrow some weak Christian; therefore God cuts their garments short, to keep them in such a trim that they might run the ways of his commandment.