What does Experience: Necessary To A Minister mean in the Bible?

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Charles Spurgeon's Illustration Collection - Experience: Necessary to a Minister
Buchsel says:: 'Orthodoxy can be learnt from others; living faith must be a matter of personal experience. The Lord sent out his disciples, saying, 'Ye shall testify of me, because ye have been with me from the beginning.' He only is a witness who speaks of what he has seen with his own eyes, heard with his own ears, and handled with his own hands. Orthodoxy is merely another form of rationalism, if it be learnt from without.'