How do the sola fideists cope with these declarations?

 By whose faith? By your faith?
Or by the faith of Christ Jesus?

How do the sola fideists cope with these declarations?

How do the sola fideists ("justification by faith, i.e. their act of believing, alone") cope with these declarations of Scripture? Are they saying one and the same justification?

1. Justification by Christ: the BASIS of Justification
- Ro 5:9 Much more then, being now justified by his blood, we shall be saved from wrath through him. 

- Ga 2:16 Knowing that a man is not justified by the works of the law, but by the faith of Jesus Christ, even we have believed in Jesus Christ, that we might be justified by the faith of Christ, and not by the works of the law: for by the works of the law shall no flesh be justified.

- Ga 2:17 But if, while we seek to be justified by Christ, we ourselves also are found sinners, is therefore Christ the minister of sin? God forbid. 

Justified by Christ's blood, justified by the faith of Jesus Christ, and justified by Christ... what justification is spoken of here? Are they the same justification by your faith?
- How does Christ's blood and Christ's faith(fulness) justify you?
- How does your faith justify you? 

Justification before God requires righteousness, and this righteousness is either by your own obedience to the law (i.e., deeds or works of the law) or by Christ's obedience to the law (i.e., His faith, or faithfulness in discharging the work of redemption). There is no justification by the works/deeds of the law!

Christ alone kept the law, completely and perfectly.
His righteousness alone meets the demands of God the Judge. 

And do you know that believing in Jesus Christ is a WORK?
Here it is, listen closely. Christ Himself said it.

John 6:28 KJT
28 Then said they unto him, What shall we do, that we might work the works of God? [i.e. the works appointed of God to be done by His children.]
29 ¶Jesus answered and said unto them, This is the work of God, that ye believe on him whom he hath sent. [i.e. this is the work God has appointed for you to work.]

Believing in Jesus Christ is a WORK required of God's children. 
Could this truth be expressed in simpler terms?
Not a few believe God requires this work from those dead in trespasses and sins.

2. Justification by God's Grace: the MANNER of justification
- Tit 3:7 That being justified by his grace, we should be made heirs according to the hope of eternal life.
- Ro 3:24 Being justified freely by his grace through the redemption that is in Christ Jesus:  [Note: justified freely by his grace, AND NOT THROUGH your faith in Christ Jesus; but through the redemption that is in Christ Jesus.]

Justified by God's grace... yes, FREELY by His grace; this repudiate the notion that there is such a thing as a grace that is not free but earned or merited - i.e. through your faith. IF it is through your faith, then your justification is by works! John 6:28-29. 

3. Justification by your Faith: the Evidence of Justification
And even those passages that speak of justification by faith... whose and what is that faith? Is it man's act of believing? Is "faith" and "believing" the same thing?

i. Romans 3:28 Therefore, we conclude that a man is justified by faith without the deeds of the law.
- ... justified by the faithfulness of Christ in His work of redemption.
- If it is by your faith, then it is by the deed of the law, your obedience to a command of God's law. 
- 1John 3:23 "And this is his commandment, that we should believe on the name of his Son Jesus Christ, and love one another, as he gave us commandment.

ii. Romans 4:2 "For if Abraham were justified by works, he hath whereof to glory; but not before God. 3 For what saith the scripture? Abraham believed God, and it was counted unto him for righteousness."
- Abraham's faith (his act of believing) was counted to him for righteousness. This is completely different from Christ's righteousness accounted to Abraham for his justification by God. 
- In this passage, Apostle Paul marshalled Abraham to REPUDIATE the Judaisers' error that ceremonial laws must be observed to be accepted by God. Apostle Paul demonstrates that Abraham EXPERIENCED the blessedness of his justified state by faith, and NOT by performing any ceremonial laws like circumcision.  

iii. Romans 5:1 "Therefore being justified by faith, we have peace with God through our Lord Jesus Christ."

- Galatians 3:24 "Wherefore the law was our schoolmaster to bring us unto Christ, that we might be justified by faith."

4. And there is justification by works as well as by faith.
i. James 2:21 "Was not Abraham our father justified by works, when he had offered Isaac his son upon the altar?"

BOTH faith (act of believing) and works of righteousness JUSTIFY EVIDENTIALLY. It is like breath and movement, both give evidence that the man is alive. 

ii. James 2:24 "Ye see then how that by works a man is justified, and not by faith only."
Works evidence a justified state by the free grace of God. Works and works of the law are entirely different things. Works justify evidentially.

Laws condemn, and no works of the law can justify a man.

Romans 3:20 "Therefore by the deeds of the law there shall no flesh be justified in his sight: for by the law is the knowledge of sin."

May our Lord grant you understanding.