6 For I desired mercy, and not sacrifice; and the knowledge of God more than burnt offerings.
The outside appearance
Israel was never deficient in this microscopical and petty breadth of mind which they possess in wonderful density to this day. With a strong sense of what might be called the mechanical sancitities of the Mosaic law, they lacked the deep probing penetration that goes to the bottom of things, and the mental amplitude that can take in "the breadth and length and height" of which Paul speaks.
They accepted and stickled for the washings, and the fastings, and the sacrifices, without seeing what was under it all -- righteousness, mercy, obedience, faith. God rebuked them more than once for the multitude of their sacrifices in the absence of the spiritual "salt" that made them acceptable -- not that the sacrifices were not enjoined, but that they were out of place when divorced from the sentiments of which God intended them to be the symbol and expression.
Nazareth Revisited Ch 25