He Declares That What A Man Sows He Will Reap (Psalms 18:25-27).
David was confident that righteousness must triumph simply because of what God is. Like him we too can know that He is and that He is a rewarder of those who diligently seek Him.
‘With the merciful you will show yourself merciful,
With the irreproachable man you will show yourself irreproachable,
With the pure you will show yourself pure,
And with the wayward you will show yourself perverse.'
He looks to God and declares that in the end He will respond to what men are. Man looks at the outward appearance, but God sees the heart. All men essentially choose the way in which they will walk, they choose their attitudes and what they set their hearts on. They choose whether they will seek God and serve Him, or whether they will be perverse and wayward. And God sees and responds to what they are.
This is the picture of the ideal. David is not claiming to be sinless. He knows he has at times fallen short. But he is expecting God to be merciful to him, as he seeks to be merciful to others, to behave irreproachably towards him as he seeks to live an irreproachable life, to behave with purity towards him as he strives to keep himself pure. All this is apparent also from his other psalms. He knew as most of us do the periods of darkness and doubt, of self reproach, and deep conviction of sin. But he also knew what it was to rise above it and set his heart on God. And he knew that a true walk with God involved mercy, and irreproachability, and purity, made possible by God's grace, and that to such God would respond.
This is, of course, looking from the manward side. Men are revealed by how they behave. By their fruits they will be known. If a man walks with God his life will reveal it.
And the contrary side is that ‘with the wayward you will show yourself perverse'. Not for David the idea that God will overlook sin in all. Those who are wayward in respect of God's ways must expect God to behave waywardly with them (Leviticus 26:23-24; Isaiah 29:9-12; Proverbs 3:34).
‘For you will save the afflicted people,
But the haughty eyes you will bring down.'
But he did not doubt that these hopes required the grace and power of God exercised on his behalf. It is God Who will save the afflicted people, and will bring down the haughty. In the end all is of God. The afflicted people are the humble and needy, those whom the world treats badly, those who face the struggles of life, and are aware of their need, and who in their need seek God. And David knows that God will step in to deliver such, and he sees himself as one of them. He puts on no great airs. He is humble before God. Without Him he knows that there is no hope. But the haughty, those who are self-seeking and seek to put God in His place, will discover that in the end they are brought down. For God is over all.