Note 2 at Acts 2:16: Peter here exhibits a perception and understanding of the scriptures which had not been characteristic of him or the other disciples before. This came as a direct result of the baptism of the Holy Spirit. Jesus said that the Holy Spirit would lead us into all truth and teach us all things (Jn. 14:26; 16:13) and this is exactly what was happening with Peter.

Receiving the baptism of the Holy Ghost is the single most important key to receiving revelation knowledge from God (see note 1 at Lk. 2:26, p. 56 and note 1 at Jn. 7:15, p. 283).