keep the feast

Boyd’s Bible Dictionary:

(joyful). Observed for joyous events (Gen. 21:8; 29:22; 40:20; Mark 6:21-22). Numerous religious feasts (Ex. 12:16; Lev. 23:21-24; Jude 12).

Strong’s Dictionary of Greek Words:

Number:
1858 (find all occurrences in KJV Bible)
Greek:
ἑορτάζω
Transliteration:
heortazo
Phonic:
heh-or-tad’-zo
Meaning:
from 1859; to observe a festival
KJV Usage:
keep the feast