Psalm 15:1-5 (ESV) A Psalm of David.
O Lord, who shall sojourn in your tent?
Who shall dwell on your holy hill?
 He who walks blamelessly and does what is right
and speaks truth in his heart;
 who does not slander with his tongue
and does no evil to his neighbor,
nor takes up a reproach against his friend;
 in whose eyes a vile person is despised,
but who honors those who fear the Lord;
who swears to his own hurt and does not change;
 who does not put out his money at interest
and does not take a bribe against the innocent.
He who does these things shall never be moved.
All the qualities listed in verses 2-5 are the result of grace lavished out on those who believe. We are completely unable to live consistently like this.
The qualities listed here take us to Christ. He is the only One who can do these things perfectly. And He did. And all those who trust Him are counted as if they had lived that way too. That is the stunning miracle of grace.
But the grace of God at work in the hearts of the faithful will enable a person to exhibit these qualities in greater and greater measure. A person comes to Christ by faith. By the power of God he now lives a righteous, honest, upright life. Such a life mean that he will never be moved.
Holiness leads to fearlessness. It produces strength and perseverance and tenacity. The last phrase of this Psalm also tells us that there are going to be things that will try to move us. The person who lives half a Christian life will not be able to stand against them. They will make him crumble. But God gives power to the faithful. He gives ability to endure to those who will put righteousness ahead of convenience, holiness ahead of popularity. The person who lives right, guards his tongue, loves his neighbour, is loyal to his friends, fears the Lord, keeps his word even if it means suffering to do so, does not lend money with interest, and will not take money at the expense of innocent people will not be moved.
God will honour such faithfulness. The reason He will honour it is so that such behaviour can continue. He will enable you to stand so that you can continue to be the person of integrity that such behaviour indicates you to be. It is not always easy to live like verses 2-5. But it is always worth it. There is going to be adversity in life. Who will be able to stand in the face of it? Those who care more about pleasing God than anything else.