"The faith
that justifies is emphatically not another work.  No, to say,
"justification by faith" is merely another way of saying "justification
by Christ".  Faith has absolutely no value in itself, it’s value lies
solely in its object.  Faith is the eye that looks to Christ.  The hand
that lays hold of him.  The mouth that drinks the water of life."  John
Stott

"God doth justify the believing man, yet not for the worthiness of
his belief, but for his worthiness who is believed"  Richard Hooker

Both are from The Cross of Christ, John Stott (p. 184, 188)

It is comforting when our faith is weak and doubts abound that we
are not saved by the quality of our faith.  We are saved because we
have put our faith in a perfect Savior not because we have perfect
faith.  It is the object of our faith (Christ) the matters most.  Weak
faith is a strong Savior will surely save, while strong faith is a weak
savior will not.  I see this is Mark 9:21-27 where a man asks Jesus to
heal his son.  Jesus tells the man that "all things are possible to one
who believes".  The man responds in brutal honestly, "I believe; help
my unbelief!"  He is saying that he does believe in Jesus, but that
there is still a lot of doubts in his heart.  This man is saying, "I am
giving you all the faith I’ve got, please give me more faith to believ
in you".  And that was enough for Jesus.

Of course we don’t want to stay there, but when we are there it is a
great relief to know that it is His worthiness not the worthiness of
our faith that makes us secure.