Paul says that a servant of God’s church must be able to “hold the mystery of the faith with a clear conscience” (1 Tim 3:9). Clearly within the Christian faith, there are mysteries. More than that, within our own limited understanding, there are apparent paradoxes.
Michael Horton, in his excellent defense of Calvinism, For Calvinism, writes on this mysterious tension.
[We must recognize] the paradox that lies at the heart of every great doctrine of the [Christian] faith. It affirms simultaneously God’s unity and trinity, Christ’s divinity and humanity, God’s sovereignty and human responsibility. Believers are urged with all seriousness to work out their salvation, and yet this salvation is already assured as a gift from the Father, in the Son, through the Holy Spirit. The kingdom of Christ is present now, inaugurated by Christ’s resurrection, and yet not fully consummated until he returns. Ignoring these tensions (the irrationalist temptation) or resolving these tensions (the rationalistic temptation) are always easy options. Living in the tension is more difficult: listening where God has spoken, but restraining our curiosity beyond his Word.