Paul admires their zeal for God, but adds that their zeal is not based on knowledge. Their zeal was too nationalistically centered, too focused on their being the “people of God” and not based on an understanding of God’s overall mission and purpose to bring salvation to the nations.
In verse 3 the emphasis is on the Jewish desire “to establish their own (righteousness)” rather than submit to the righteousness of God. It is not that they thought they were accomplishing their own righteousness as opposed to God’s, but rather the false idea that their unique relationship with God, as His chosen people made them right.
The Israelites knew God’s grace, but they had failed to recognize why God had chosen them and that His grace would be extended to all nations through a Messiah that would come through the line of David.
The Christian church can fall into the trap of exclusivity through a sense of self-righteousness – aside from grace. What ends up happening, even before we realize it, is we have embraced an identity outside of Christ’s redemptive work in our lives and made it the focus of our religious practice – just like the religious people of Jesus day.
This sort of self-focused exclusivity within the church not only creates barriers to those who “outside” our belief system; it makes the proclamation of the Gospel secondary to these other agendas. This cannot be, because of the urgency of the hour.