People often struggle with the idea of the trinity.

How can God be a man and a Spirit and God all at the same time?
The answer is easier when we remember He is God.
Nothing is too hard for God.
“I am the LORD, the God of all mankind. Is anything too hard for me? Jeremiah 32:27
He fills all of the universe at the same time, knows all of our thoughts continually, sees perfectly in total darkness.
Still His power is not diminished.
When God had a son he did not create another God.
God inhabited flesh and bones.
Why?
Because He is Holy and Just.
A man would have to atone for the sins of mankind.
But no man was the perfect offering required for sacrifice.
God loved us so much that He personally came to endure the hardships of life and still be able to love His enemies.
He allowed them to kill Him on a Roman cross.
He bore our punishment and endured our shame because He loved us.
Then three days later He overcame the grave to prove He can do the same thing for all who believe in Him as Lord and Savior.
“Jesus said to her, “I am the resurrection and the life. He who believes in me will live, even though he dies; and whoever lives and believes in me will never die. Do you believe this?”
John 11:25,26