The following original spelling text from the 1609 edition is copied from A Casebook on Shakespeare's Sonnets, ed. Gerald Willen and Victor B. Reed (New York: Crowell, 1964).
When my love sweares that she is made of truth,
I do beleeve her, though I know she lyes,
That she might thinke me some untuterd youth,
Unlearned in the worlds false subtilties.
Thus vainley thinking that she thinkes me young,
Although she knowes my dayes are past the best,
Simply I credit her false speaking tongue,
On both sides thus is simple truth supprest:
But wherefore sayes she not she is unjust?
And wherefore say not I that I am old?
O loves best habit is in seeming trust,
And age in love, loves not t'have yeares told.
Therefore I lye with her, and she with me,
And in our faults by lyes we flattered be.