I just re read my post, and though it does tell you about why Hebrews 5:7
is there, it doesn't explain what it meant for Jesus to "fear" God.
Here now is my Vines dictionary of New Testament Greek words and their meanings.. and an alternative translation and I think you'll see this is easy to understand.
In other versions of the Bible, for example the New International Version, this verse reads like this
"during the days of Jesus's life on earth, he offered up prayers and petitions with loud cries and tears to the one who could save him from death, and he was heard because of his REVERENT SUBMISSION."
The word in the Greek that we translate "fear" in English, has many different meanings. In this verse the word for fear that is used is the Greek word "Eulabeia" which according to Vines, "signifies firstly caution, then reverence godly fear." It constitues a piety of mind towards God. It is a knowledge of the awesomeness of God and reverence towards Him based on the knowledge I am nothing compared to Him."
One of the alternative words for "fear" in the New Testament is Phobos which means to be in dread or terror and when in relation to God this is used in such verses as Phillipians 2:12 where we are told to work out our salvation with fear and trembling"
This is obviously not what was intended here.. as the NIV translation shows, Jesus was not fearful or afraid when he prayed (this verse needs to be read in relation to Luke 22:39 -46) but in reverential knowledge of the one He was praying too... total obedience and submission to His will.
Hope this helps
Carol