"All sorts of subjects are eargerly pursued; but the knowledge of God is neglected. . . . Yet to know God is man's chief end, and justifies his existence. Even if a hundred lives were ours, this one aim would be sufficient for them all."
This quote is from Calvin's commentary on Jeremiah 9:24 found in the introduction of the Institutes... see
John Calvin, The Institutes of the Christian Religion (ed. John T. McNeill; trans. Ford Lewis Battles; 2 vols.; LCC; Philadelphia: Westminster Press, 1960), Lxxi.