Because of the great zeal and devotion which I experienced in executing well the two pictures which His Highness commissioned me to make — the one being Christ's dead body being laid in the tomb, and the other Christ arising from the dead to the consternation of the guards — these same two pictures are now finished through studious application, so that I am now disposed to deliver the same and so to afford to His Highness. For in these two paintings the greatest and most natural movement has been expressed, which is also the main reason why they have taken so long to execute.

Letter to Constantijn Huygens on paintings commissioned by the imperial court (12 January 1639), as quoted in Painters on Painting (1963) by Eric Protter, p. 78