Never be doubtful 

At that time Jesus was led by the Spirit into the desert
to be tempted by the devil.
He fasted for forty days and forty nights,
and afterwards he was hungry.
The tempter approached and said to him,
“If you are the Son of God,
command that these stones become loaves of bread.”
He said in reply,
“It is written:
One does not live on bread alone,
but on every word that comes forth
from the mouth of God.”

Then the devil took him to the holy city,
and made him stand on the parapet of the temple,
and said to him, “If you are the Son of God, throw yourself down.
For it is written:
He will command his angels concerning you
and with their hands they will support you,
lest you dash your foot against a stone.”
Jesus answered him,
“Again it is written,
You shall not put the Lord, your God, to the test.”
Then the devil took him up to a very high mountain,
and showed him all the kingdoms of the world in their magnificence,
and he said to him, "All these I shall give to you,
if you will prostrate yourself and worship me.”
At this, Jesus said to him,
“Get away, Satan!
It is written:
The Lord, your God, shall you worship
and him alone shall you serve.”

Then the devil left him and, behold,
angels came and ministered to him. (Mt 4:1-11)

Temptation is a type of test. God allows us to be tested, not because He does not know what is in our hearts but to allow us to know our own limits. Jesus allows the devil to test Him to teach us how to respond in similar situations. Jesus, Incarnate, wanted to share every limit of the human condition. As He was hungry after fasting, the devil tried to take advantage of this weakness. His response teaches us to never doubt that God will abandon us in times of trial.