Thomas Watson’s sermons on the Westminter Shorter Catechism, A Body of Divinity was Banner of Truth’s first published book in 1958.
This work was first published as part of a Body of Practical Divinity in 1692. Then it was reprinted in 1890.
Here’s Watson’s beginning statements regarding Justification:
‘Being justified freely by his grace.’ Rom iii 24.
QXXXIII: What is justification?
A: It is an act of God’s free grace, whereby he pardons all our sins, and accepts us as righteous in his sight, only for the righteousness of Christ, imputed to us, and received by faith alone.
Justification is the very hinge and pillar of Christianity. An error about justification is dangerous, like a defect in a foundation. Justification by Christ is a spring of the water of life. To have the poison of corrupt doctrine cast into this spring is damnable. It was a saying Luther, ‘that after his death the doctrine of Justification would be corrupted.’ In these latter times, the Arminians and Socinians have cast a dead fly into this box of precious ointment.” (226)