Matthew 15:1-20. Jesus defined what defiles a person; it is not what he eats, but what comes out of his mouth. Ceremonial cleansing is just for show. J
In Numbers 14 the people rebelled and refused to go into the promised land. As a punishment the people had to continue wandering for forty years in the desert until that generation, with the exception of Caleb and Joshua had passed away. Meanwhile the people tried to take on the Amalekites in their own strength, but failed miserably.
Psalm 21, of David. The New Testament references from Revelation 14 seems to fit. When I read this Psalm, the battle hymn of the republic kept ringing in my ears.