Doubt and uncertainty disappear when these words of Mrs. Eddy in Miscellany are understood (p. 129): "Trust God to direct your steps. Accept my counsel and teachings only as they include the spirit and the letter of the Ten Commandments, the Beatitudes, and the teachings and example of Christ Jesus."
A wavering trust in an unknown God would certainly not be very practical, but Mrs. Eddy reveals God as omniscience, omnipresence, omnipotence, and omniaction. This revelation resulted from her faithful study of the Scriptures, from her spiritual understanding of the Ten Commandments and the Beatitudes, and from her humble following of the Way-shower.
To trust the eternal God is to trust good, to trust spiritual power on earth as in heaven, and to trust divine Providence here and now. So, to put our whole trust in God implies a spiritual understanding of Him.