Martin Luther.

“When Moses writes that God created Heaven and Earth and whatever is in them in six days, then let this period continue to have been six days, and do not venture to devise any comment according to which six days were one day. “But, if you cannot understand how this could have been done in six days, then grant the Holy Spirit the honor of being more learned than you are”. (Martin Luther, What Martin Luther Says: A Practical Home Anthology for the Active, p. 1523)