God is a Spirit, and we must worship him in spirit and in truth. Are you contending that the natural man, that cannot discern the things of the Spirit, and thinks them to be foolishness, neither can he know them because they are spiritually discerned, will call upon the name of a spiritual Lord?
Romans 10 is directed by Paul to the biggest part of spiritual Israel (Rev 5:9) who are a disobedient and gainsaying (stubborn) people, (Rom 10:21), because they sought their righteousness not by faith, but as if it were by the works of the law, for they stumbled at that stumblingstone (Rom 9:33).
Salvation=deliverance, saved=delivered and save=deliver, according to Greek interpretation.
Rom 10, verse 1 begins by Paul praying for the disobedient Israel that they might be saved (delivered from their ignorance). He affirms that they have a ZEAL of God (defending God), but not according to knowledge, for they being ignorant of God's righteousness, and going about to establish their own righteousness, (by their works), having not submitted themselves unto the righteousness of God..
Zeph 3:11-13, gives more on explaining how spiritual Israel is divided by the disobedient part and the remnant of Israel, who are an afflicted and poor people, and they shall trust in the name of the Lord. The remnant of Israel shall not do iniquity, nor speak lies; neither shall a deceitful tongue be found in their mouth; for they shall lie down, and none shall make them afraid. Paul is one of the remnant.
Most on this forum are among the disobedient Israel (lost sheep of the house of Israel) who are depending upon their works of righteous for their eternal deliverance.