Verses with the word warfare in the New Testament (3 verses):

1 Corinthians 9:7
Who goeth a warfare any time at his own charges? who planteth a vineyard, and eateth not of the fruit thereof? or who feedeth a flock, and eateth not of the milk of the flock?

2 Corinthians 10:4
(For the weapons of our warfare are not carnal, but mighty through God to the pulling down of strong holds;)

1 Timothy 1:18
This charge I commit unto thee, son Timothy, according to the prophecies which went before on thee, that thou by them mightest war a good warfare;