Only those who obey Christ receive that salvation which God promised to the righteous

Only those who obey Christ will be saved:

Hebrews 5:9 And being made perfect, he became the author of eternal salvation unto all them that obey him;

Those who do not want to obey Christ, simply do not love Christ:

John 14: 23 Jesus answered and said unto him, If a man love me, he will keep my words: and my Father will love him, and we will come unto him, and make our abode with him. 24He that loveth me not keepeth not my sayings: and the word which ye hear is not mine, but the Father's which sent me.

"For we maintain that a man is justified by faith apart from works of the Law," (Rom. 3:28).

Only those who work are justified. But not by their works. They are justified by God because they work in accordance to His Will. Again, as it is written:

Romans 2:13(For not the hearers of the law are just before God, but the doers of the law shall be justified.

"But to the one who does not work, but believes in Him who justifies the ungodly, his faith is reckoned as righteousness," (Rom. 4:5).

This is a reference to Abraham. Did Abraham work? Sure he did. By faith Abraham obeyed God:
Hebrews 11: 8By faith Abraham, when he was called to go out into a place which he should after receive for an inheritance, obeyed; and he went out, not knowing whither he went.

That is the obedience of faith. It isn't faith alone. But faith accompanied by works of obedience.

“I do not nullify the grace of God; for if righteousness comes through the Law, then Christ died needlessly," (Gal. 2:21).

Righteousness does not come through the Law. But the Law leads us to righteousness:
Galatians 3: 24Wherefore the law was our schoolmaster to bring us unto Christ, that we might be justified by faith.
"You foolish Galatians, who has bewitched you, before whose eyes Jesus Christ was publicly portrayed as crucified? 2 This is the only thing I want to find out from you: did you receive the Spirit by the works of the Law, or by hearing with faith? 3 Are you so foolish? Having begun by the Spirit, are you now being perfected by the flesh?" (Gal. 3:1-3).

The Law justifies no man. But if you don't keep the Law in the Commandments, God won't justify you. Very simple.

If you don't add to faith, virtue and works of charity, God will not save you.

2 Peter 1 5And beside this, giving all diligence, add to your faith virtue; and to virtue knowledge;
6And to knowledge temperance; and to temperance patience; and to patience godliness;
7And to godliness brotherly kindness; and to brotherly kindness charity.
8For if these things be in you, and abound, they make you that ye shall neither be barren nor unfruitful in the knowledge of our Lord Jesus Christ.
But he that lacketh these things is blind, and cannot see afar off, and hath forgotten that he was purged from his old sins.