HEBREWS 1.3-4: He is the radiance of the glory of God and the exact imprint of his nature, and he upholds the universe by the word of his power. After making purification for sins, he sat down at the right hand of the Majesty on high, (4) having become as much superior to angels as the name he has inherited is more excellent than theirs. (ESV)
When Jesus Christ was on earth, He was the earthly revelation of the exact likeness and essence of God the Father. During Jesus’ time in the upper room with His disciples, Philip requested that Jesus show them the Father. Jesus responded in John 14.9 by saying, “Whoever has seen me has seen the Father.” (ESV)
In the verse from Hebrews above we are taught that Jesus is the “exact imprint” of God the Father’s nature. The word translated “exact imprint” was used at that time to refer to the impression stamped on coins, and other similar ideas. The Gingrich and Danker lexicon says that the word translated “nature” in verse 3 means, “substantial nature, essence, actual being, reality”.
So when people looked at Jesus when He was on the earth, they were looking at the exact holiness and righteousness of God the Father. This is because Jesus was and is one with God the Father, as He taught His disciples in John chapter 17.
When Jesus taught about the proper interpretation of God’s Law, He was teaching exactly the way God the Father wanted it taught. Likewise, the ways in which Jesus interacted with people, either for encouragement or reproof or the working of miracles, were all of the exact nature and essence of the thinking and aim and intent of God the Father.