Give to him that asks of you; and from him that would borrow of you, turn not away. (Matthew 5:42)
In the Law of Moses it was forbidden to require interest on any loan between members of the house of Israel. Also, lenders were forbidden from not lending on account of the year of the jubilee being near wherein all debts would be forgiven.
And as you desire that men should do to you, do also to them likewise. For if you love only those who love you, what reward have you? For sinners also do even the same. And if you do good to them who only do good to you, what reward have you? For sinners also do even the same. And if you lend to them of whom you hope to receive, what reward have you? For sinners also lend to sinners, to receive as much again. But love your enemies, and do good, and lend hoping for nothing again, and your reward shall be great, and you shall be the children of the Highest. For he is kind unto the unthankful and the evil. Be therefore merciful as your Father also is merciful. Judge not and you shall not be judged. Condemn not and you shall not be condemned. Forgive and you shall be forgiven. Give and it shall be given unto you — good measure, pressed down and shaken together, and running over shall men give into your bosom. For with the same measure that you mete, it shall be measured to you again. (Luke 6:31-38)
Here Christ is saying you are to lend to those who would borrow of you expecting nothing in return. If they pay you back? Great! You weren't expecting it in the first place.
Karma is a true principal. It may function in a length of time longer than most desire but it is still a true principal. How you measure to your fellow man is how God will in turn measure you.
What profit is it, my brethren, for a man to say he has faith, and has not works? Can faith save him? Yea, a man may say, I will show you I have faith without works. But I say, show me your faith without works and I will show you my faith by my works. … Even so faith, if it has not works, it is dead, being alone. Therefore will you know, O vain man, that faith without works is dead and cannot save you. (James 2:14,17-18)
There are those who teach that we are saved by the Grace of Christ without consideration for whether or not we do good works by obeying his commandments. The scriptures teach a different standard. Christ can forgive you of all your sins but you must do something to merit the reward in heaven that you desire. The concept is “grace for grace”. By showing grace to others you merit in return a reward of grace from God.
… [F]or all have sinned and come short of the glory of God, therefore being justified only by his grace, through the redemption that is in Christ Jesus ... (Romans 3:23-24)
No matter how much of a reward we may merit through obedience to Christ's commandments we nevertheless will still fall short. God will make up the lack for the faithful. Therefore trust in Him and rely on Him for he is mighty to save.
