David was weak before certain temptations and his falls were grievous, but his repentance was deep and his returns to God were sincere. He never failed to regard God as supreme over him and the bestower of all his blessings. He is called the man after God's own heart, and it is also said that his heart was perfect before God. His spirit of devout worship has never been surpassed. His Psalms, in all the ages, have been accepted as expressing the true yearning after righteousness and a longing for closer communion with God.
David, in the fifteenth Psalm, expresses the thought of the earnest and reverent worshippers of his time. This Psalm declares the necessity of moral purity in those who would be citizens of Zion and dwellers in the holy hill.
"Lord, who shall abide in thy tabernacle? Who shall dwell in thy holy hill? He that walketh uprightly, and worketh righteousness, and speaketh the truth in his heart. He that backbiteth not with his tongue, nor doeth evil to his neighbor, nor taketh up a reproach against his neighbor. In whose eyes a vile person is condemned; but he honoreth them that fear the Lord. He that sweareth to his own hurt and changeth not. He that putteth not out his money to usury, nor taketh reward against the innocent. He that doeth these things shall never be moved."
The description, "He that putteth not out his money to usury," is direct and unqualified. There could be no mistaking its meaning. Those who were guilty could not claim to be citizens of Zion. There is no qualifying clause behind which the usurer could take refuge and escape condemnation.
This Psalm, prepared by the king, was chanted in the great congregation, and was a prick to the consciences of the sinners and a public reproof of all the sins mentioned. He that putteth out his money to increase received thus a public reproof in the great worshipping assembly.
Solomon, endowed with unequaled wisdom and able so clearly to discern the right, places among his proverbs a direct denunciation of this sin.
Prov. 28:8: "He that by usury and unjust gain increaseth his substance, he shall gather it for him that will pity the poor."
In this proverb the gain of usury is classed with unjust gain that shall not bless the gatherer. This is in entire harmony with other proverbs in which those who practice injustice and oppression are declared to be wanting in true wisdom and receive no benefit themselves.
"The righteousness of the upright shall deliver them: but transgressors shall be taken in their own naughtiness."
"As righteousness tendeth to life; so he that pursueth evil pursueth it to his own death."