The modern world provides many dilemmas for Christians and one of these is how to manage all the resources that we are given, including money. An extreme position on this point would be to say that we should all give away our possessions and follow Him in faith, so that the problem of investment decisions should never arise. In Scripture there is a clear instruction: “Lay not up for yourselves treasures upon earth, where moth and rust doth corrupt, and where thieves break through and steal” (Matthew 6:19) Some will make that choice, and work among the poor but many more will lead a Christian life in middle class society.
For most of us investing a portion of own money for the education of our children and care of ourselves and relatives when we are older is a sensible and prudent measure. There is nothing inherently wrong about building an investment plan alongside other financial decisions like tithing and buying property to create a comfortable and welcoming Christian home.
As with many moral issues, the issue is more about the degree of our involvement in the issue, and whether it constitutes something that gets in the way of our Christian faith. It is clearly not defensible to build vast wealth on high risk, speculative investments, or in funds, industries or companies which pursue sinful or exploitative business practices. This would bring the Church into disrepute and lay us open to accusations of selfishness and causing actual harm to others.
The primary aim should be good and safe stewardship of our money, not profit making for selfish gain. There are some ethical investment funds, also, which are designed to support developing countries, or new businesses in deprived area, and our investments here would surely do much good. In the end it comes down to a personal choice which should be reached with prayerful examination of our conscience, and as part of a family and church strategy.