This is a belief of Hinduism and Buddhism – that a person’s actions control the good and bad that happens to them in this life – and when associated with reincarnation will determine their next life.
It considers a person gets what they deserve, yet with Christianity Jesus took the punishment for what we deserve. Any good we do can’t outweigh the bad we have done and the sinful nature we were born with (Ps 51:5; Eccl 7:20; Isa 59:2, 64:6). While the Bible speaks of sowing and reaping, this is not a hard and fast rule when viewed from the earthly perspective but will be impartially and fully outworked at the final judgement where we all will be recompensed for our lives (2 Cor 5:9,10; Gal 6:7-10; Heb 9:27). Karma implies that a person has the ability to save themselves by their actions and thus does not need to rely on God for salvation. This is contrary to the Bible’s teaching that it is impossible to work one’s way to heaven or out of judgement (Rom 3:20; Gal 2:15-17; Eph 2:8-10). Its only those who have chosen Christ and are righteous (because of His grace) who experience eternal life (Mt 25:46; Jn 3:16-18,36). Karma is an impersonal force of cause and effect that can’t deal with the sin problem, whereas God is a loving person whose forgiveness releases people from the eternal consequences of their actions when there is genuine repentance, although there are still earthly effects.