Question 64: But does not this doctrine make men careless and profane?

Answer:
By no means: for it is impossible that those, who are implanted into Christ by a true faith, should not bring forth fruits of thankfulness. (a)

(a) Matt.7:18 A good tree cannot bring forth evil fruit, neither can a corrupt tree bring forth good fruit.
John 15:5 I am the vine, ye are the branches: He that abideth in me, and I in him, the same bringeth forth much fruit: for without me ye can do nothing.