@makingwisethesimple
Do we have to explicitly call upon Him[Jesus] by name?
When our own wisdom falters, i think it's best to rely on the Scriptures...
Rom 10:9 Because if you confess the Lord Jesus, and believe in your heart that God has raised Him from the dead, you shall be saved.
Rom 10:10 For with the heart one believes unto righteousness, and with the mouth one confesses unto salvation.
Of course, salvation is not limited to a particular nation or race of people.
Rom 10:11 For the Scripture says, "Everyone believing on Him shall not be put to shame."
Rom 10:12 For there is no difference both of Jew and of Greek, for the same Lord over all is rich to all who call on Him.
Commandment 3 states :
Exo 20:7 Thou shalt not take the name of the LORD thy God in vain; for the LORD will not hold him guiltless that taketh his name in vain.
You see, here we are to understand that 'name' is not just a superficial calling word for convenience of reference, rather it is what stands as identity to a particular being. When I refer to you by name, I'm also making a reference to your nature, character and all else that you stand for. It is our 'names' that are written in the Book of Life. So, God places importance on how His name is used or called upon because you're actually referring to His person when you do so. This is again why the name of Jesus is so important - it refers to all that He is, all that He has done and all that He can do.
Rom 10:13 For whosoever shall call upon the name of the Lord shall be saved.
And this takes us, logically, to the next few verses -
Rom 10:14 How then shall they call on him in whom they have not believed? and how shall they believe in him of whom they have not heard? and how shall they hear without a preacher?
Rom 10:15 And how shall they preach, except they be sent? as it is written, How beautiful are the feet of them that preach the gospel of peace, and bring glad tidings of good things!
And then,
Rom 10:17 So then faith cometh by hearing, and hearing by the word of God.
There is no use in confessing the name of the Lord if you don't believe in all that He stands for - and this is impossible for a true believer. I have read accounts of how tribal people received visions of Jesus Christ and when missionaries began to preach to them, they readily confessed Jesus as Lord. There have been others who've known the Lord and worshipped only Him but had to wait for a preacher to tell them the name of Jesus. What matters is that you believe in the person of Jesus for your salvation based on His righteousness and sacrifice on the cross. What matters is that you put your faith in Him to be resurrected into an eternal life in God's presence.
I think that we will all be very surprised to see, on that day, those who are called into God's kingdom and those who aren't.
I totally agree. As I said in my previous post, each of us should work out our own salvation and not speculate on others'.
Php 2:12 Wherefore, my beloved, as ye have always obeyed, not as in my presence only, but now much more in my absence, work out your own salvation with fear and trembling.
Many who are relying on their own merit and works 'in faith' to gain entrance into the Kingdom of Heaven will also themselves be surprised on the Day of the Lord.
Mat 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.
Mat 7:22 Many will say to me in that day, Lord, Lord, have we not prophesied in thy name? and in thy name have cast out devils? and in thy name done many wonderful works?
Mat 7:23 And then will I profess unto them, I never knew you: depart from me, ye that work iniquity.
I sometimes wonder if there will be some 'Christians' who aren't and some Muslims that are.
I'm not sure what you meant here. If you mean that some may enter the Kingdom even though they've never entered a fellowship, church, read Scriptures - then yes, it is possible provided they've believed in Christ. Take the example of the thief on the cross. All true believers are part of the Church of Christ. Can a muslim be saved - yes. Can a muslim remain a muslim - no, the moment he believes in Christ, he becomes a Christian. Does he have to attend service in a Christian church then - I don't know, God may call him to be an evangelist in the mountains where there may be no church - maybe, he'll set up a church there; he's anyway a member of Christ's church. Can he worship any other god but the living God - no. Can he put his faith in any other name but Jesus - no.
Am I laying down rules on what a Christian should do or shouldn't - no, who am I to lay down rules - i'm merely stating what a true believer, by nature, will choose to do.
If I've misunderstood anything, please correct me.