The name "Yah" appears in several Psalms, including:
Psalm 68:4: This verse stresses the name "Yah" and calls on people to "sing praises to His name"
Psalm 89:9: The short form "Yah" appears in this verse
Psalm 150:1: This verse calls on people to "praise Yah in His sanctuary"
Psalm 135: This Psalm begins with "Praise Yah! Praise Yahweh's name!"
"Yah" is a shortened form of the Hebrew name for God, "YHWH", which is often rendered as "Yahweh" by modern scholars. "Yah" appears in the Bible about 50 times, including 24 times in the phrase "Hallelujah". It is also incorporated into many Biblical proper names, such as "Eliyahu