Q 38: What is the textual proof that Faith increases and decreases?

{that they may grow more in Faith along with their (present) Faith}.

{...and We increased them in guidance}.

{And Allah increases in guidance those who walk aright}.

{While as for those who accept guidance, He increases their guidance}.

{..and that the believers may increase in Faith}.

 {As for those who believe, it has increased their Faith}.

{...therefore, fear them." But it (only) increased them in Faith}.

{And it only added to their Faith and to their submissiveness (to Allah)}.

"By Him in Whose Hand is my life, if your state of mind remains the same as it is in my presence and you are always busy in remembrance (of Allah), the Angels will shake hands with you in your beds and in your paths but, Hanzala, time should be devoted (to the worldly affairs) and time (should be devoted to prayer and meditation). He (the Holy Prophet) said this thrice ".