A Psalm of Asaph.1Truly God is good to Israel,
to those who are pure in heart.
2But as for me, my feet had almost stumbled,
my steps had nearly slipped.
3 For I was envious of the arrogant
when I saw the prosperity of the wicked.
4For they have no pangs until death;
their bodies are fat and sleek.
5They are not in trouble as others are;
they are not stricken like the rest of mankind.
6Therefore pride is their necklace;
violence covers them as a garment.
7Their eyes swell out through fatness;
their hearts overflow with follies.
8They scoff and speak with malice;
loftily they threaten oppression.
9They set their mouths against the heavens,
and their tongue struts through the earth.
10Therefore his people turn back to them,
and find no fault in them.
11And they say, “How can God know?
Is there knowledge in the Most High?”
12Behold, these are the wicked;
always at ease, they increase in riches.
13All in vain have I kept my heart clean
and washed my hands in innocence.
14For all the day long I have been stricken
and rebuked every morning.
The faith even of strong believers may sometimes be sorely shaken and ready to fail them. These are storms that will try the firmest anchors.
See here what it is to be religious; it is to cleanse our hearts, in the first place by repentance and regeneration, and then to wash our hands in innocency by a universal reformation of our lives. It is not in vain to do this, not in vain to serve God and keep his ordinances; but good men have been sometimes tempted to say, “It is in vain,” and “Religion is a thing that there is nothing to be got by”, because they see wicked people in prosperity. But, however the thing may appear now, when the pure in heart, those blessed ones, shall see God (Matthew 5:8), they will not say that they cleansed their hearts in vain.
Matthew Henry, Commentary on the Whole Bible, Psalm LXXIII, vs. 1-14, highlights