cultivating lovingkindness

Since a single mind moment cannot contain both a wholesome (kusala) and an unwholesome (akusala) emotional tone, learning to develop the quality of loving kindness moment after moment in a sustained manner has the effect of purifying the mind as it locks out competing unwholesome states.
Andy Olendzki, Pali Scholar

“If one frequently thinks and ponders upon thoughts of loving kindness, one has abandoned thoughts of ill-will to cultivate thoughts of loving kindness, and then one’s mind inclines to thoughts of loving kindness.” - Andy paraphrasing from the Dvedhavitakka Sutta (M 19)

Thus the mind stream or stream of consciousness is purified by both the presence of a wholesome state and the absence of an unwholesome state.
Andy

nibbana, nirvana

The goal of Buddhist practice, cessation, is not annihilation, but an extinction of the suffering of wanting things to be different than they are. When we come into balance of internal and external circumstances we are free to live and love without grasping. We are not indifferent, but responsible, acting with skill and wisdom.

Indeed the sage who's fully quenched
Rests at ease in every way;
No sense desires adhere to him[her]
Whose fires have cooled, deprived of fuel.
All attachments have been severed,
The heart's been lead away from pain;
Tranquil [s/he] rests with utmost ease,
The mind has found its way to peace.

Andy Olendzki's translation of Cullavagga 6:4.4