Martin Luther discusses what makes faith sure and steadfast in his Commentary on Galatians:
Faith, if it is to be sure and steadfast, must lay hold upon nothing else but Christ alone, and in the conflict and terrors of conscience it has nothing else to lean on but this precious pearl Christ Jesus. So, he who apprehends Christ by faith, although he be terrified with the law and oppressed with the weight of his sins, yet he may be bold to glory that he is righteous. How? Even by that precious jewel Christ Jesus, whom he possesses by faith.
People talk often about their faith, but in our society it seems like people place āfaith in faith.ā Which is misplaced faith. Our faith is only effective as the object it is placed on. Only faith whose object is Jesus Christ can we have certainly in its effectiveness for salvation. For it is by grace alone through faith alone in Christ alone can we have hope of heaven.
HT: Ray Ortlund