(48) Time and posture prescribed for developing Metta
Furthermore, the manner of taking a posture and the time for the purpose of developing metta has been prescribed as follows:
Tittham while standing, or, caram - while walking, or, nissinno va while sitting i.e. seating, or, sayano va - while lying, yavata - as far as possible, vitamiddho-assa - should be free from torpor, i.e. free from sleepiness, or rather, free from the spell of dozing. Tavata - for so long as one becomes sleepy and has not yet fallen asleep, etam satim - this mindfulness, the precursor of Metta, adhittheyya - should be developed by way of observing and dwelling upon it, or rather, contemplation.
Metta should, in fact, be developed not only while sitting but also while standing. It must also be developed while taking a walking exercise along the corridor to relax the limbs after prolonged sitting; while lying in bed before falling asleep, and for so long as one is awake, it must be continually developed. This is to say that an interval for respite should be only for the period when one is fast asleep. The moment a person is roused from sleep when full consciousness revives, one should carry on developing metta beginning from the time he becomes alert and mentally alive to the occasion. In this regard, Mindfulness along with metta should be contemplated and incessantly developed. If he is a person who has achieved jhana, metta-jhana combined with Mindfulness should be developed always. This is to let oneself plunge in a trance of metta-jhana. Developing metta bhavana as stated, is to abide in a noble and perfect state. It has been preached that all Buddhas had extolled this metta as being the Dhamma which, if developed, amounts to abiding in this Sasana in a holy and perfect state (Brahma-vihara).