Be pure in heart

If a man has peace in his heart, does it require him to quote scriptures to prove it?

If a man who quotes scriptures has a heart full of strife, is not his heart still evil?

If a man's heart is filled with warmhearted love for God and for people, has he not obeyed the principle requirements of scriptures?

If a man quotes scripture in his conversation and in all his writings, yet his heart is full of hatred, has he not disobeyed the principle commandments of scripture?