There is a portion of a verse that is often quoted...

There is a portion of a verse that is often quoted using it to describe that God causes misfortune for the just as well as the unjust. God "sendeth rain on the just and on the unjust."
 

When put in context, this portion of scripture means quite the opposite. It is actually saying that God is merciful to both the just and the unjust and Jesus wants us to be merciful as well.

"Ye have heard that it hath been said, Thou shalt love thy neighbour, and hate thine enemy. But I say unto you, Love your enemies, bless them that curse you, do good to them that hate you, and pray for them which despitefully use you, and persecute you; that ye may be the children of your Father which is in heaven: for he maketh his sun to rise on the evil and on the good, and sendeth rain on the just and on the unjust. For if ye love them which love you, what reward have ye? do not even the publicans the same? And if ye salute your brethren only, what do ye more than others? do not even the publicans so? Be ye therefore perfect, even as your Father which is in heaven is perfect." - Matthew 5:43-48 KJV

There are many verses in the Bible that speak of rain being a blessing. Here are just a few verses that speak of rain as a blessing:

"The LORD shall open unto thee his good treasure, the heaven to give the rain unto thy land in his season, and to bless all the work of thine hand: and thou shalt lend unto many nations, and thou shalt not borrow." - Deuteronomy 28:12 KJV

"Be glad then, ye children of Zion, and rejoice in the LORD your God: for he hath given you the former rain moderately, and he will cause to come down for you the rain, the former rain, and the latter rain in the first month." - Joel 2:23 KJV

"Nevertheless he left not himself without witness, in that he did good, and gave us rain from heaven, and fruitful seasons, filling our hearts with food and gladness." - Acts 14:17 KJV

"For the earth which drinketh in the rain that cometh oft upon it, and bringeth forth herbs meet for them by whom it is dressed, receiveth blessing from God:" - Hebrews 6:7 KJV

(Also: 1 Kings 8:35-36/ 2 Chronicles 6:26-27, James 5:7)