Some make a mockery of the holy things of God. One part of the year they will be holy; a rotten, foolish affection of people that are popish. In Lent they will use a little austerity, oh! they will please God wondrously! but before and after they are devils incarnate. So they make that part of the year as a good parenthesis, in an unlearned and unwitty speech. A good parenthesis is unseemly in a wicked speech, and a good piece is unseemly in a ragged garment; so their lives that make a good show then (and there are few that do so, they are scarce among us; men are such atheists that there is not outward reformation, but if there be), if they give themselves leave to be civil, and to respect holy things a little time, afterward they return to their looseness again. Doth this patching out of a holy life please God? No, no! ‘I have sworn, and I will perform it, that I will keep thy righteous statutes,’ saith David, Ps. 119:106. And St Paul, ‘I have resolved to be so to the end;’ I will be myself still. So where grace is, there is a resolution against all sin for the time to come. If you entertain not this resolution, to walk ‘in holiness and righteousness all the days of your life,’ Luke 1:75, acknowledge no benefit by Christ’s redemption, and come not near the holy things of God.
Richard Sibbes, The Complete Works of Richard Sibbes, vol. 3 (Edinburgh; London; Dublin: James Nichol; James Nisbet and Co.; W. Robertson, 1862), 313.
I made a meme alongside the same principle. Lent: Because living like a Christian the rest of the week is just too much trouble.