開門偈:
捲箔逢彌勒
開門見釋迦
三參禮無上
遊戱法王宮

開門偈
open door gatha
(開 kāi open; 門 mén door; 偈 jì gatha [short for 偈陀])

捲箔逢彌勒
roll screen meet Maitreya
(捲 juǎn to roll up; 箔 bó screen; 逢 féng meet; 彌勒 Mílè Maitreya

開門見釋迦
open door see Shakyamuni

三參禮無上
three three honor nothing higher

遊戱法王宮
swim play dharma king palace
(遊 yóu to swim hsk2; 戱 xì to play; 法 fǎ Dharma; 王 wáng king; 宮 gōng palace)

This is part of a traditional Korean Buddhist ritual called “Bathing the Spirit” (沐浴篇), or just “Bathing” (灌浴), which, in turn is part of the traditional “49 Day Ceremony” (四十九齋), to be performed 49 days after someone has died.
More information (in Korean, Chinese, and, in some cases, also English) can be found here:
https://blog.daum.net/01193704043/12411906
http://www.bulmusic.com/nbuilder/community/module/board/boardRead.php?table=tb_ib__left23&keyset=b_wc&reqPage=2&b_bno=113
https://folkency.nfm.go.kr/en/topic/detail/199
http://www.koreanbuddhism.net/bbs/board.php?bo_table=4010&wr_id=5