LOVING-KINDNESS
“The four divine abidings were mentioned next to the recollections as meditation subjects. They are loving-kindness, compassion, gladness and equanimity. A meditator, who wants to develop firstly loving-kindness among these, if he is a beginner, should sever the impediments and learn the meditation subject. Then, when he has done the work connected with the meal and got rid of any dizziness due to it, he should seat himself comfortably on a well-prepared seat in a secluded place. To start with, he should review the danger in hate and the advantage in patience.
Why? Because hate has to be abandoned and patience attained in the development of this meditation subject, and he cannot abandon unseen dangers and attain unknown advantages.” — Visuddhimagga
While often used as a modern meditation, the cultivation of metta, or lovingkindness, is a practice used to develop the basis, the foundation for a serious meditation practice. While a point of focus and recollection, this topic of meditation is taught and practice in conjuction with other protective practices, which when done well, can lead to stream-entry.
“Understanding duḥkha is the basis of developing compassion.” — SDY
Often the first of the brahmavihāras, metta or lovingkindness, is a pillar of mental cultivation guided by our wish for ourselves and others to be free from suffering.
“Just as oneself, all beings desire happiness; having seen that, one should develop kindness toward all beings.” — translation
Coming from a rich tradition with a complete view of the world, phenomena, and the natural laws of kamma, the understanding of metta in Buddhadhamma is complete when given in context of the oral instructions on mettabhāvanā. We cannot rely on practices that are easily found and shared amongst the vast array of material found on the internet, as we don’t know their source, their rate of success, nor any unintended results.
There are traditional meditation manuals like the Vissuddhimagga and the Vimuttimagga which go into the practices in detail. For beginners, and even for those with some understanding and practice, the instructions contain many things that we cannot always extract from reading the words.
If one wishes to understand lovingkindess for themselves, and build the stability to wish for and maintain lovingkindness for other beings, it is best to learn a traditional practice focused on this topic with a teacher who not only understands, but can assuage any concerns that may arise while one is practicing in the beginning, in the middle, and as one gains experience.