Vengenance belongs to the LORD.

Romans 12:14 Bless them which persecute you: bless, and curse not. 15 Rejoice with them that do rejoice, and weep with them that weep. 16 Be of the same mind one toward another. Mind not high things, but condescend to men of low estate. Be not wise in your own conceits. 17 Recompense to no man evil for evil. Provide things honest in the sight of all men. 18 If it be possible, as much as lieth in you, live peaceably with all men. 19 Dearly beloved, avenge not yourselves, but rather give place unto wrath: for it is written, Vengeance is mine; I will repay, saith the Lord. 20 Therefore if thine enemy hunger, feed him; if he thirst, give him drink: for in so doing thou shalt heap coals of fire on his head. 21 Be not overcome of evil, but overcome evil with good.

Looking at the three words higlight above:

Recompense (Strong's Lexicon)

1) to be in a covenant of peace, be at peace

a) (Qal)

1) to be at peace

2) peaceful one (participle)

b) (Pual) one in covenant of peace (participle)

c) (Hiphil)

1) to make peace with

2) to cause to be at peace

d) (Hophal) to live in peace

2) to be complete, be sound

a) (Qal)

1) to be complete, be finished, be ended

2) to be sound, be uninjured

b) (Piel)

1) to complete, finish

2) to make safe

3) to make whole or good, restore, make compensation

4) to make good, pay

5) to requite, recompense, reward

c) (Pual)

1) to be performed

2) to be repaid, be requited

d) (Hiphil)

1) to complete, perform

2) to make an end of

Condesend ( Strong's Lexicon)

1) to lead away with or together

2) metaph. to be carried away with

a) of a thing, i.e. by a thing, so as to experience with others the force of that which carries away

b) to yield or submit one's self to lowly things, conditions, employments: not to evade their power

Vengeance (Strong's Lexicon)

1) a revenging, vengeance, punishment

With respect to 2Cr 7:11: "...meeting out of justice; doing justice to all parties. See on Luk 18:3; 21:22. The word has, however, the sense of requital (see on Rom 12:19; compare 2Th 1:8 ), and carries with it, etymologically, the sense of of vindication, as Luk 18:7, 8." (Marvin Vincent, Word Studies in the New Testament, 3:329)

According to Romans 12, we are to try to live peacably with all men, in compasion for them. We are not to be led away by our own desires, but TRUST THE LORD, that HIS VENGEANCE will be completed for us. It is a warning both for us, and for those that come against us. We are called to love our enemies and even go as far as to feed and clothe them if necessary.