Psalm 51:10

"Create in me a pure heart, O God, and renew a steadfast spirit within me."

stead·fast

  [sted-fast, -fahst, -fuhst]

adjective

1.

fixed in direction; steadily directed: a steadfast gaze.

2.

firm in purpose, resolution, faith, attachment, etc., as aperson: a steadfast friend.

3.

unwavering, as resolution, faith, adherence, etc.

4.

firmly established, as an institution or a state of affairs.

5.

firmly fixed in place or position.

pure

  [pyoor] adjective, pur·er, pur·est.

1.

free from anything of a different, inferior, or contaminatingkind; free from extraneous matter: pure gold; pure water.

2.

unmodified by an admixture; simple or homogeneous.

3.

of unmixed descent or ancestry: a pure breed of dog.

4.

free from foreign or inappropriate elements: pure Attic Greek.

5.

clear; free from blemishes: pure skin.