Holy Spirit in Christianity

In most Christian churches, the Holy Spirit, or Holy Ghost, is the third person of the Trinity, a God made up of three persons: God the Father, God the Son, and God the Holy Spirit, who share the same qualities and essence and are therefore One God. Christians who don't believe in the Trinity have a big difference in their beliefs about the Holy Spirit.
In Christian theology, pneumatology is the study of the Holy Spirit.
Since Christianity does indeed have a historical relationship with Judaism, theology experts often identify the Holy Spirit with the concept of the "Ruach Hakodesh" found in Jewish scripture, suggesting that Jesus may have just been expanding upon these Jewish concepts.
Names.
Hebrew Bible.
Source:
New Testament.
Depending on context: