Contradiction with Matthew 6:1
Contradicts by emphasizing giving alms in secret, whereas Psalms 40:9 speaks of declaring righteousness to a great congregation.
Matthew 6:1: Take heed that ye do not your alms before men, to be seen of them: otherwise ye have no reward of your Father which is in heaven. [alms: or, righteousness] [of your: or, with your]
Contradiction with Proverbs 27:2
Suggests letting others praise you instead of proclaiming, contrary to speaking of God's righteousness openly in Psalms 40:9.
Proverbs 27:2: Let another man praise thee, and not thine own mouth; a stranger, and not thine own lips.
Contradiction with Matthew 7:6
Advises not casting pearls before swine, contrasting with openly declaring God's righteousness.
Matthew 7:6: Give not that which is holy unto the dogs, neither cast ye your pearls before swine, lest they trample them under their feet, and turn again and rend you.
Contradiction with John 7:4
Indicates not doing good works in secret if you seek to be known, whereas Psalms 40:9 supports proclaiming openly.
John 7:4: For [there is] no man [that] doeth any thing in secret, and he himself seeketh to be known openly. If thou do these things, shew thyself to the world.
Contradiction with Proverbs 10:19
Warns that with many words sin is unavoidable, contrasting with speaking freely of God's righteousness in Psalms 40:9.
Proverbs 10:19: In the multitude of words there wanteth not sin: but he that refraineth his lips [is] wise.