Wait on the Lord , And keep His way, And He shall exalt you to inherit the land; When the wicked are cut off, you shall see it. I have seen the wicked in great power, And spreading himself like a native green tree. Yet he passed away, and behold, he was no more; Indeed I sought him, but he could not be found.
Psalm 37:34-36 (NKJV)
To wait on the Lord is an act of faith. I may not see the results now, but I shall wait and believe in His timing and trust that He is working behind the scene.
David also added that the wicked might seem to prosper but their success will not last forever.