Swearing Before God!

I swear to God and using God's Name in vain.
Is it wrong to swear an oath before God?
If it is, I should not have raised my right hand and swore the
oath of enlistment, when I entered into military service. I
swore allegiance to this nation, to protect and defend the
United States of America against all enemies foreign and
domestic. Was that wrong?
We read of men of God in the Holy Scriptures who swore oaths
before God, and called God to Witness their words before men,
which I do not believe was sin. Their oaths before God
strengthened their words and promises to each other and to
God.