So too, at the present time there is a remnant chosen by grace.
When you think about it, that's pretty amazing. Since Adam and Eve, God has always kept some people who love and serve him in the world. He has sustained them and provided enough for them to remain trusting in him and to stay alive.
In this passage in Romans, Paul is speaking specifically about a Jewish remnant, and he gives the example of Elijah from 1 Kings 19:10-18. Elijah says to God that he is the only one left who truly follows God in Israel. God proves him wrong, promising that there were 7000 who had not bowed the knee to Baal.
Likewise, we never know who is one of God's people. When you feel like you're the only Christian out there, then pray, ask for God's help. Yes, it's possible that you are - in that case then you can know that God will sustain you and provide for you as he always has for his people in the past and as he always will in the future. But don't lose hope! God has people serving him who we don't know about - we don't know it all and we need to trust in him.
Paul says that this remnant is chosen by grace. That means that God has saved us entirely by his grace - not by anything we have done. What a wonderful thing that is! We don't have to fear losing our salvation because we have it for free - Jesus died and his death covers all our sin. If we turn to him in repentance and faith then we will be saved, and we will be totally forgiven, even though we still stuff it up. Jesus' sacrifice was big enough to cover all our sin if we are his people. We don't have to fear that we will be 'un-saved'. No one who is truly chosen by God will turn away from him - only those who are faking it or who don't truly understand it will turn away, because they have not been saved by grace.
An interesting parallel to this is found in Genesis 18 when Abraham asks God if he would preserve Sodom and Gomorrah if only 10 righteous people were in it (v32). God removed Lot from that city and destroyed it. God won't destroy the world while his people are in it - I think that means that before God destroys the world he will take his people to be with him. Maybe I'm wrong there - I haven't researched it much at all, but it's an interesting thought.
God preserves a remnant, are you in it?