In the Buddha's Words: An Anthology of Discourses from the Pali Canon by Bhikkhu Bodhi

5. MEDITATION
(1) The Development of Loving-Kindness
(Mettābhāvanā Sutta)

“Monks, whatever grounds there are for making merit productive of a future birth, all these do not equal a sixteenth part of the liberation of mind by loving-kindness. The liberation of mind by loving-kindness surpasses them and shines forth, bright and brilliant.

“Just as the radiance of all the stars does not equal a sixteenth part of the moon’s radiance, but the moon’s radiance surpasses them and shines forth, bright and brilliant, even so, whatever grounds there are for making merit productive of a future birth, all these do not equal a sixteenth part of the liberation of mind by loving-kindness. The liberation of mind by loving-kindness surpasses them and shines forth, bright and brilliant.

“Just as in the last month of the rainy season, in the autumn, when the sky is clear and free of clouds, the sun, on ascending, dispels the darkness of space and shines forth, bright and brilliant, even so, whatever grounds there are for making merit productive of a future birth, all these do not equal a sixteenth part of the liberation of mind by loving-kindness. The liberation of mind by loving-kindness surpasses them and shines forth, bright and brilliant.

“And just as in the night, at the moment of dawn, the morning star shines forth, bright and brilliant, even so, whatever grounds there are for making merit productive of a future birth, all these do not equal a sixteenth part of the liberation of mind by loving-kindness. The liberation of mind by loving-kindness surpasses them and shines forth, bright and brilliant.”

(It 27; 19–21)