In context the scripture reads -
Ps. 49:6-9: “Those who are trusting in their means of maintenance, and who keep boasting about the abundance of their riches, not one of them can by any means redeem even a brother, nor give to God a ransom for him; (and the redemption price of their soul is so precious that it has ceased to time indefinite) that he should still live forever and not see the pit.”
Therefore, in context, no 'imperfect human' can provide the means to deliver someone else from sin and death. His money cannot buy eternal life, and his soul laid down in death, being the wages that are to come to him anyway because of sin, has no value toward delivering anyone.
“In Adam all are dying,” said the apostle Paul. (1 Corinthians 15:22) The ransom thus had to involve the death of the exact equal of Adam—a perfect human. (Romans 5:14) No other kind of creature could balance the scales of justice. Only a perfect human, someone not under the Adamic death sentence, could offer “a corresponding ransom”—one corresponding perfectly to Adam. (1 Timothy 2:6) It would not be necessary for untold millions of individual humans to be sacrificed so as to correspond to each descendant of Adam. The apostle Paul explained: “Through one man [Adam] sin entered into the world and death through sin.” (Romans 5:12) And “since death is through a man,” God provided for the redemption of mankind “through a man.” (1 Corinthians 15:21)
God arranged to have a perfect man voluntarily sacrifice his life. According to Romans 6:23, “the wages sin pays is death.” In sacrificing his life, the ransomer would “taste death for every man.” In other words, he would pay the wage for Adam’s sin. (Hebrews 2:9; 2 Corinthians 5:21; 1 Peter 2:24) This would have profound legal consequences. By nullifying the death sentence upon Adam’s obedient offspring, the ransom would cut off the destructive power of sin right at its source.—Romans 5:16.