BUDDHIST PALI CHANTING: Mahāsamaya Sutta by Ven Moneyyo
The Mahāsamaya Sutta (Dīgha Nikāya/Long Discourses #20) is a very famous chant. It is considered supremely auspicious, and particularly liked by all 'Devas' (Angels/Deities/Benevolent Spirits).
In every Buddha's livetime, there occurs an event where the Devas of our world system, and even from several adjacent worlds, assemble to meet the Buddha and his Sangha of disciples. In the case of our Buddha Gotama, this event happened in the Great Forest near Kapilavatthu, the hometown of Buddha, where he grew up as a prince.
As not all of the 500 monks present are able to see spirits, the Buddha explains which devas have arrived, and gives the names of their leaders, which class of devas they belong to, and the numbers of their retinue.
It is widely believed that whenever this sutta is recited, devas feel attracted to come to listen with great joy and in large numbers.
An english translation of the Mahāsamaya Sutta is available here: