Spirit of truth is the name that Jesus (Yeshua‘) used for the Holy Spirit. He also called Him the Comforter, Helper, Advocate, and Counselor. The Holy Spirit reveals truth; He convicts of sin and He guides us into truth.
Spirit of Truth in Greek:
To pneuma tēs alētheias
Strong’s Concordance numbers: 4151, 228
Bible reference: John 14:17; 15:26; 16:13
When he, the Spirit of truth, comes, he will guide you into all the truth. He will not speak on his own; he will speak only what he hears, and he will tell you what is yet to come. (John 16:13 NIV)