生きとし生けるもの

• 生(い)き (iki) is the 連用形(れんようけい) (ren'yōkei) of 生(い)きる (ikiru);
• と (to) is a particle which expresses the meaning "all", "every", when used in conjunction with the same verb twice, as seen here
• し (shi) is an intensifying particle, also found in e.g. いつしか (itsushika), かならずしも (kanarazushimo);
• 生ける (ikeru) is an adnominal meaning "living"; see there for further origin;
• もの (mono, “thing, person, being”) has its usual meaning.

Compare with ありとあらゆる (ari to arayuru).

• (Tokyo) いきとし・いける・もの [íꜜkì tò shì ìkéꜜrù mònóꜜ] (Atamadaka + Nakadaka + Odaka – [1]-[2]-[2])

• IPA^(key): [ikʲi̥ to̞ ɕi̥ ike̞ɾɯ̟ mo̞no̞]

生(い)きとし生(い)けるもの • (iki to shi ikeru mono) 

1. all living creatures
   • 2016, 凋叶棕 (Diao ye zong), “心綺楼 [Shinkirō]”, in 伝 [Tsutae]:

     生(い)きとし生(い)けるものたちよ
     その長(なが)き命(いのち)を以(も)って如何(いか)にあるのか

     iki to shi ikeru mono tachi yo
     sono nagaki inochi o motte ika ni aru no ka

     O living creatures of the world
     How do you live those long lives of yours?