Some outfits such as Jehovah's Witnesses try changing Scripture in order to match their beliefs rather than the other way around. What does God say about changing Scripture?
God doesn't Want Us Changing Scripture!
Ye shall not add unto the word which I command you, neither shall ye diminish ought from it, that ye may keep the commandments of the LORD your God which I command you. (Deuteronomy 4:2)
What thing soever I command you, observe to do it: thou shalt not add thereto, nor diminish from it. (Deuteronomy 12:32)
For I testify unto every man that heareth the words of the prophecy of this book, If any man shall add unto these things, God shall add unto him the plagues that are written in this book: And if any man shall take away from the words of the book of this prophecy, God shall take away his part out of the book of life, and out of the holy city, and from the things which are written in this book. (Revelation 22:18-19)
Scripture or Man's Opinion?
All scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness: That the man of God may be perfect, throughly furnished unto all good works. (2 Timothy 3:16-17)
There is a way which seemeth right unto a man, but the end thereof are the ways of death. (Proverbs 14:12 and Proverbs 16:25)
If our beliefs conflict with the Scripture, change our beliefs not the Scripture. Changing Scripture may seem right to us, but read the Proverbs passages above.
This does not mean that we cannot paraphrase Scripture, especially when we are sharing with another Christian or witnessing to a lost person and do not have a Bible with us.
The question is: Why are you altering Scripture? If you are memorizing paraphrases of verses, intending to have the same meaning as the actual verses so as to use them while sharing with others, not a problem. After all, few Christians carry a Bible with them everywhere they go. However, if you do not like or believe a verse or passage and change it more to your liking or what you believe, watch out!
 All scripture references are from the King James Version unless otherwise noted. Please see my about page for why I chose this translation.