The bible is clear on usury. Usury is spoken against in a number of places. It's categorised along with unjust gain - basically theft or dishonesty. Hence my description of it as dishonest plunder. I don't believe its logically consistent to expect that the Lawgiver who prohibited usury takes profit from the same.
Deuteronomy 23:19 Thou shalt not lend upon usury to thy brother; usury of money, usury of victuals, usury of any thing that is lent upon usury:
Proverbs 28:8 He that by usury and unjust gain increaseth his substance, he shall gather it for him that will pity the poor.
Nehemiah 5:10 I likewise, and my brethren, and my servants, might exact of them money and corn: I pray you, let us leave off this usury.
You're negating the fact that, in this parable, Jesus is the Lord who reckons with his servants when he returns.
He calls those who gave him back what he initially gave them with usury, or interest, or "gain" on his initial investment "good and faithful servants". Not only that, but they are also rewarded with rulership and an entrance into the joy of their Lord.
How then is usury or interest allegedly bad here when Jesus refers to it as being "good" and rewards it?
Matthew 25:14
For
the kingdom of heaven is as a man travelling into a far country,
who called his own servants, and delivered unto them his goods.
Matthew 25:15
And unto one he gave five talents, to another two, and to another one; to every man according to his several ability; and straightway took his journey.
Matthew 25:16
Then he that had received the five talents went and traded with the same, and made
them other five talents.
Matthew 25:17
And likewise he that
had received two, he also gained other two.
Matthew 25:18
But he that had received one went and digged in the earth, and hid his lord's money.
Matthew 25:19
After a long time the lord of those servants cometh, and reckoneth with them.
Matthew 25:20
And so he that had received five talents came and brought other five talents, saying, Lord, thou deliveredst unto me five talents: behold, I have gained beside them five talents more.
Matthew 25:21
His lord said unto him, Well done, thou good and faithful servant: thou hast been faithful over a few things, I will make thee ruler over many things: enter thou into the joy of thy lord.
Matthew 25:22
He also that had received two talents came and said, Lord, thou deliveredst unto me two talents: behold, I have gained two other talents beside them.
Matthew 25:23
His lord said unto him, Well done, good and faithful servant; thou hast been faithful over a few things, I will make thee ruler over many things: enter thou into the joy of thy lord.
Matthew 25:24
Then he which had received the one talent came and said, Lord, I knew thee that thou art an hard man, reaping where thou hast not sown, and gathering where thou hast not strawed:
Matthew 25:25
And I was afraid, and went and hid thy talent in the earth: lo,
there thou hast
that is thine.
Matthew 25:26
His lord answered and said unto him,
Thou wicked and slothful servant, thou knewest that I reap where I sowed not, and gather where I have not strawed:
Matthew 25:27
Thou oughtest therefore to have put my money to the exchangers, and
then at my coming I should have received mine own with usury.
Matthew 25:28
Take therefore the talent from him, and give
it unto him which hath ten talents.
Matthew 25:29
For unto every one that hath shall be given, and he shall have abundance: but from him that hath not shall be taken away even that which he hath.
Matthew 25:30
And cast ye the unprofitable servant into outer darkness: there shall be weeping and gnashing of teeth.