statrei said:
Then you need to update your idea of the Christian life. The meaning of Christianity is that our will are linked to the will of the Master in such a way that our expression in everything is His expression. It matters not what we call it. If we claim to be Christian we are claiming to speak in His name. You seem to think that only some people do so. You have been poorly taught. Discard those teachers and read the Bible for yourself.

I just love posters who assume others just say what they have been taught by others and haven't searched scripture for themselves. (I am being a bit sarcastic here!!)
If we are speaking about what is in scripture, taught in scripture, we have the authority of scripture which is inspired by God to back us up.
White was writing about stuff that is not in scripture and calaiming the spirit of prophesy! As a result, the SDA have made this statement:
http://www.adventist.org/beliefs/fundamental/index.html
18. The Gift of Prophecy:
One of the gifts of the Holy Spirit is prophecy. This gift is an identifying mark of the remnant church and was manifested in the ministry of Ellen. G. White . As the Lord's messenger, her writings are a continuing and authoritative source of truth which provide for the church comfort, guidance, instruction, and correction. They also make clear that the Bible is the standard by which all teaching and experience must be tested. (Joel 2:28, 29; Acts 2:14-21; Heb. 1:1-3; Rev. 12:17; 19:10.)
As Christians, we shouldn't go around proclaiming whatever we wish OR beleiving whatever someone says JUST because they claim to be Christians. That doesn't them give the authority to make stuff up!! Once you leave scripture, you are out on the proverbial limb. Just claiming the name of Jesus will not help:
Mat 7:21 "Not everyone who says to Me, 'Lord, Lord,' will enter the kingdom of heaven, but he who does the will of My Father who is in heaven {will enter.}
Mat 7:22 "Many will say to Me on that day, 'Lord, Lord, did we not prophesy in Your name, and in Your name cast out demons, and in Your name perform many miracles?'
Mat 7:23 "And then I will declare to them, 'I never knew you; DEPART FROM ME, YOU WHO PRACTICE LAWLESSNESS.'