When is the Holy Spirit first mentioned in the Bible?

Answer:
Very good question – Actually the Holy Spirit is referred to in the very first verse of the Bible and even more specifically in the 2nd verse of Genesis 1.

I have included the passage in both English and Hebrew for you to see.

Genesis 1:1-2 In the beginning [re’shiyth] God [‘elohiym] created [bara’] [‘eth] the heaven [shamayim] and [‘eth] the earth [‘erets]. And the earth [‘erets] was [hayah] without form [tohuw], and void [bohuw]; and darkness [choshek] was upon the face [paniym] of the deep [tehowm]. And the Spirit [ruwach] of God [‘elohiym] moved [rachaph] upon [`al] the face [paniym] of the waters [mayim].

In verse 1 the Hebrew word [elohiym] is actually plural for God and referring to the fact the Father, Son and Holy Ghost were all present at the beginning of all things.

In verse 2, [ruwach] literally means the breath or wind of God referring specifically to the Holy Spirit.

Good question!
Pastor Brad