Very Biblical. Don't know why more do not do it, other than tradition. It is a result to the over-exuberance of our Pentecostal brothers. Hand raising in many Baptist Churches began to be seen as a "Pentecostal" thing. However it is seen throughout scripture:
Psalm 63:4 ESV
So I will bless you as long as I live; in your name I will lift up my hands.
Psalm 141:2 ESV
Let my prayer be counted as incense before you, and the lifting up of my hands as the evening sacrifice!
1 Kings 8:54 ESV
Now as Solomon finished offering all this prayer and plea to the Lord, he arose from before the altar of the Lord, where he had knelt with hands outstretched toward heaven.
Ezra 9:5 ESV
And at the evening sacrifice I rose from my fasting, with my garment and my cloak torn, and fell upon my knees and spread out my hands to the Lord my God,
Psalm 134:2 ESV
Lift up your hands to the holy place and bless the Lord!
Lamentations 3:41 ESV
Let us lift up our hearts and hands to God in heaven:
Nehemiah 8:6 ESV
And Ezra blessed the Lord, the great God, and all the people answered, “Amen, Amen,” lifting up their hands. And they bowed their heads and worshiped the Lord with their faces to the ground.
Psalm 28:2 ESV
Hear the voice of my pleas for mercy, when I cry to you for help, when I lift up my hands toward your most holy sanctuary.
1 Timothy 2:8-10 ESV
I desire then that in every place the men should pray, lifting holy hands without anger or quarreling; likewise also that women should adorn themselves in respectable apparel, with modesty and self-control, not with braided hair and gold or pearls or costly attire, but with what is proper for women who profess godliness—with good works.
Deuteronomy 32:40 ESV
For I lift up my hand to heaven and swear, As I live forever,
Lamentations 2:19 ESV
“Arise, cry out in the night, at the beginning of the night watches! Pour out your heart like water before the presence of the Lord! Lift your hands to him for the lives of your children, who faint for hunger at the head of every street.”
1 Kings 8:38 ESV
Whatever prayer, whatever plea is made by any man or by all your people Israel, each knowing the affliction of his own heart and stretching out his hands toward this house,
1 Kings 8:22 ESV
Then Solomon stood before the altar of the Lord in the presence of all the assembly of Israel and spread out his hands toward heaven,
Hope that helps. I, for one, lift my hands all the time. Not because I feel I have to, just because it comes naturally.