|Should we call on the name of the Lord, or not?|
Joel 2:32 And it shall come to pass, that whosoever shall call on the name of the LORD shall be delivered: for in mount Zion and in Jerusalem shall be deliverance, as the LORD hath said, and in the remnant whom the LORD shall call.
Matthew 7:21 Not every one that saith unto me, Lord, Lord, shall enter into the kingdom of heaven; but he that doeth the will of my Father which is in heaven.
Micah 3:4 Then shall they cry unto the LORD, but he will not hear them: he will even hide his face from them at that time, as they have behaved themselves ill in their doings.
Romans 10:13 For whosoever shall call upon the name of the Lord shall be saved.
The question posed: So will all who call the Lord's name be saved, or not?
Regarding Joel 2:32: The preceding verses make it clear that what is in view is a specific time in Joel's eschatological future, the "day of the Lord" (2:31).
Acts 2:21 and Rom. 10:13 are alluding to Joel and so are answered the same way.
In contrast, Micah refers to a specific upcoming temporal judgment against the people, and the word "cry" (za'aq, to shreik out of anguish or danger) does not mean "call upon."
Matthew 7:21 is not of any relevance to the OT verses and itself does not refer to the "Lord" in a titular sense as in Rom. 10:13. The word "Lord" here is kurios and is the normal title for any person in authority (like our "sir"). The people are recognizing Jesus' obvious authority but are not "calling on his name" -- they are, rather, calling out to him.