Kindness is to be given to ALL, we are to show kindness to ALL, it i deserved by ALL.
You will not find Grace defined as underserved kindness in ANY lexicon or encyclopedia.
Grace is Charis in Greek:
1) grace
a) that which affords joy, pleasure, delight, sweetness, charm, loveliness: grace of speech
2) good will, loving-kindness, favour
a) of the merciful kindness by which God, exerting his holy influence upon souls, turns them to Christ, keeps, strengthens, increases them in Christian faith, knowledge, affection, and kindles them to the exercise of the Christian virtues
3) what is due to grace
a) the spiritual condition of one governed by the power of divine grace
b) the token or proof of grace, benefit
1) a gift of grace
2) benefit, bounty
4) thanks, (for benefits, services, favours), recompense, reward
Never will you find kindness being conditional or undeserving in the NT.