Our ancestral druids taught that the sun is vitally central to all earthly life.
So the bonfire or altar candle, like the sun, is vitally central to spiritual life, and the hearth fire is vitally central to daily life. The hearth fire, in whatever form or forms, warms the home, provides the household with the means to cook food and prepare herbal medicines, and protects from the dark, while providing a place to gather together to socialize and work. Therefore it is both the functional center of everyday living and the spiritual heart of the home.
This might literally be a fireplace, where special things are placed and around which family and friends gather at various times. In my home, as we are without this feature, it is the kitchen stove, with a shrine placed nearby containing a candle and an offering dish at which prayers are said and offerings are made, to offer respect and gratitude for these many gifts.
The hearth is the domain of the goddess Bríde, She of the Sacred Fires. She is generally represented at their hearth with an icon, symbol or figurine, such as a Bríde's cross or a corn dolly. A candle lit here demonstrates Her vital presence, as does a fire in a fireplace or wood stove. I have both a Bríde's cross over my oven and a corn dolly on the shrine beside it, to honor and represent Brìde and Her blessings.
In the Carmina Gadelica we are told that it was the woman of the house's duty to raise the hearth fire each morning, with prayers said and blessings asked, and each night she banked it down again to preserve the vital spark, also with prayers and requests for protection. I observe this practice in mornings when I cook my breakfast and make my tea, and again in the evening, when I shut off the house lights, but turn on the light over the stove for a night-light. During my morning prayer I make an offering of oats or milk to Brìde, a gift in gratitude and exchange for Her blessings and gifts.
These are the English translations of the prayers I like to use, adapted or taken from the Carmina Gadelica:
Raising the Hearth fire prayer
I will kindle my fire this morning
In presence of holy Brìde
The encirclement of Brìde
On the fire, and on the floor,
And on the household all.
Brìde, kindle you within me your Eternal Flame;
May it guide me and bless me this day.
Smooring the Hearth prayer, said while securing the house at night:
The sacred Three
Oh! this eve,
And every night,
Each single night.