Kindness appears in Paul’s letters to the Ephesians and Colossians and in the wisdom of Proverbs.
In Ephesians 4:32:
32 And be ye kind one to another, tenderhearted, forgiving one another, even as God for Christ’s sake hath forgiven you.
In Colossians 3:12:
12 Put on therefore, as the elect of God, holy and beloved, bowels of mercies, kindness, humbleness of mind, meekness, longsuffering;
In Proverbs 11:17:
17 The merciful man doeth good to his own soul: but he that is cruel troubleth his own flesh.