A poem from Christina Rossetti's Monna Innominata sonnet sequence (it's not really called 'A Blessing' but that's how I think of it).
Amor che a nullo amato amar perdona. - Dante
Amor m'addusse in sì gioiosa spene. - Petrarca
O my heart's heart, and you who are to me
More than myself myself, God be with you,
Keep you in strong obedience leal and true
To Him whose noble service setteth free,
Give you all good we see or can foresee,
Make your joys many and your sorrows few,
Bless you in what you bear and what you do,
Yea, perfect you as He would have you be.
So much for you; but what for me, dear friend?
To love you without stint and all I can
Today, tomorrow, world without an end;
To love you much and yet to love you more,
As Jordan at his flood sweeps either shore;
Since woman is the helpmeet made for man.