There are some who site the key difference between the Old Testament and the New Testament to be God’s dealing with individuals in the New Testament. It is true that God does deal with individuals in the New Testament. However, he also dealt with individuals in the Old Testament.
Peter Adam in his book Hearing God’s Words Exploring biblical spirituality points out that individualism is a product of the Enlightenment. He also notes that it is one of the weaknesses of Evangelical spirituality.
“Individualism was not a product of the Reformation, but of the enlightenment. This individualism has meant that the gospel itself has been distorted into a message for individuals. Only one summary of the gospel in the New Testament comes in the form of Christ’s love for the individual, and that is Galatians 2:20, where Paul writes of ‘the Son of God, who loved me and gave himself for me’. In every other case it is corporate, as in God’s love for the world (John 3:16), Christ’s love for the church (Eph. 5:25), the gospel for all the Gentiles (Rom. 16:26) the need to make disciples of all nations (Matt. 28:19).
“God’s love for the individual is a consequence of the gospel, not the heart of the gospel. This has big implications for Evangelicalism, which has always prided itself on getting the gospel right! Here it has particular implications for spirituality, for it means that genuine biblical spirituality will reflect and express this corporate gospel. Many traditions of spirituality tend towards individualism: Evangelical spirituality, if it is biblical, will not fall into the same trap. Stanley Grenz tells us that spirituality for a postmodern age will need to be communitarian rather than individualistic, and Christianity that is lived as well as believed (Grenz 1996: 167-169). This is biblical spirituality.”
Here is God’s instruction for dealing with individuals in the Old Testament. “Fathers shall not be put to death because of their children, nor shall children be put to death because of their fathers. Each one shall be put to death for his own sin.” (Deut. 24:16). This is not God dealing with people, but God instruction Israel how to deal with people. God’s dealing with people is not limited by his instruction to Israel regarding the administration of capital punishment. This verse is in the midst of a context of instruction from God regarding how his people are to treat the poor. Verse 14, “You shall not oppress a hired worker who is poor and needy”. Verse 19, “When you reap your harvest…and forget a sheaf…you shall not go back and get it. It is shall be for the sojourner, the fatherless, and the widow, that the LORD may bless you in all the work of your hands.”