I don’t see sufficient Scriptural support for what is usually stated as “justification by faith alone” but the idea of Mary being “Mother of God” is contrary to Scripture in every way.
Naturally the term wouldn’t appear in Scripture.
Justification by faith is in the Bible. Several places, and the most referred to is in Romans 3 (pasted below). The "alone" part came from Luther and then Calvin clarifying what Paul said below about works. So here is Romans 3 with pertinent bold highlights:
9 What then? Are we better than they? Not at all. For we have previously charged both Jews and Greeks that they are all under sin. 10 As it is written: “There is none righteous, no, not one; 11 There is none who understands; There is none who seeks after God. 12 They have all turned aside; They have together become unprofitable; There is none who does good, no, not one.” 13 “Their throat is an open tomb; With their tongues they have practiced deceit”; “The poison of asps is under their lips”; 14 “Whose mouth is full of cursing and bitterness.” 15 “Their feet are swift to shed blood; 16 Destruction and misery are in their ways; 17 And the way of peace they have not known.” 18 “There is no fear of God before their eyes.” 19 Now we know that whatever the law says, it says to those who are under the law, that every mouth may be stopped, and all the world may become guilty before God. 20 Therefore by the deeds of the law no flesh will be justified in His sight, for by the law is the knowledge of sin.
21 But now the righteousness of God apart from the law is revealed, being witnessed by the Law and the Prophets, 22 even the righteousness of God, through faith in Jesus Christ, to all and on all who believe. For there is no difference; 23 for all have sinned and fall short of the glory of God, 24 being justified freely by His grace through the redemption that is in Christ Jesus, 25 whom God set forth as a propitiation by His blood, through faith, to demonstrate His righteousness, because in His forbearance God had passed over the sins that were previously committed, 26 to demonstrate at the present time His righteousness, that He might be just and the justifier of the one who has faith in Jesus.
27 Where is boasting then? It is excluded. By what law? Of works? No, but by the law of faith. 28 Therefore we conclude that a man is justified by faith apart from the deeds of the law. 29 Or is He the God of the Jews only? Is He not also the God of the Gentiles? Yes, of the Gentiles also, 30 since there is one God who will justify the circumcised by faith and the uncircumcised through faith. 31 Do we then make void the law through faith? Certainly not! On the contrary, we establish the law.
Then in Ephesians 2:
4 But God, who is rich in mercy, because of His great love with which He loved us, 5 even when we were dead in trespasses, made us alive together with Christ (by grace you have been saved), 6 and raised us up together, and made us sit together in the heavenly places in Christ Jesus, 7 that in the ages to come He might show the exceeding riches of His grace in His kindness toward us in Christ Jesus. 8 For by grace you have been saved through faith, and that not of yourselves; it is the gift of God, 9 not of works, lest anyone should boast. 10 For we are His workmanship, created in Christ Jesus for good works, which God prepared beforehand that we should walk in them. So the NT is clear. We are Justified by faith. It is a legal declaration made by The Father based on the Son's saving actions, not our actions.