And first, as regards the necessity or voluntariness of good works, it is manifest that in the Augsburg Confession and its Apology these expressions are often used and repeated that good works are necessary. Likewise, that it is necessary to do good works, which also are necessarily to follow faith and reconciliation. Likewise, that we necessarily are to do and must do such good works as God has commanded. Thus also in the Holy Scriptures themselves the words necessity, needful, and necessary, likewise, ought and must, are used concerning what we are bound to do because of God's ordinance, command, and will.
Therefore the expressions or propositions mentioned [that good works are necessary, and that it is necessary to do good] are unjustly censured and rejected in this Christian and proper sense, as has been done by some; for they are employed and used with propriety to rebuke and reject the secure, Epicurean delusion, by which many fabricate for themselves a dead faith or delusion which is without repentance and without good works, as though there could be in a heart true faith and at the same time the wicked intention to persevere and continue in sins, which is impossible; or, as though one could, indeed, have and retain true faith, righteousness, and salvation even though he be and remain a corrupt and unfruitful tree, whence no good fruits whatever come, yea, even though he persist in sins against conscience, or purposely engages again in these sins, all of which is incorrect and false.
Solid Declaration of the Formula of Concord, 4, 14-15.
This was todays Confessions reading in the TDP.