What we know about God from the book of Hebrews

"God" The first word of the book.  God is presumed and exists  Heb 1:1

God acted in different times of history.

Heb 1:1 God, who at sundry times and in divers manners spake in time past unto the fathers by the prophets,
Heb 1:2 Hath in these last days spoken unto us by his Son, whom he hath appointed heir of all things, by whom also he made the worlds;

• God communicated. 
  • He used prophets as his instrument of communication.
  • He spoke to us by his Son
    • Ths Son is another personage of God who by this statement was of the same kind as God
    • The Son was given authority "appointed heir of all things,"
    • The Son was creator and exercised divine power. "by whom also he made the worlds;"
      
  • He clarified for us his son's status by saying,
    • Heb 1:3 Who being the brightness of his glory, and the express image of his person, and upholding all things by the word of his power, when he had by himself purged our sins, sat down on the right hand of the Majesty on high;
      Heb 1:4 Being made so much better than the angels, as he hath by inheritance obtained a more excellent name than they.
      Heb 1:5 For unto which of the angels said he at any time, Thou art my Son, this day have I begotten thee? And again, I will be to him a Father, and he shall be to me a Son?
      • Psa 2:7 I will declare the decree: the LORD hath said unto me, Thou art my Son; this day have I begotten thee.