There are at least two reasons why this hard truth is good news to us. The first is that it means that if we are in the number of the elect, we cannot be removed from them. The second is that, despite our pitiable efforts and failures in the field of evangelism, God will still save His elect.
The first means that an individual’s state of salvation—yours and mine—is not in a state of flux. Stop looking to yourself to figure out whether you are a part of the number of the elect. Look instead to Christ, because only the elect can do that. If you can look to Christ for your salvation from God’s wrath, then you don’t need to worry about being destined to that wrath. No one, not even you, is able to snatch you from Christ’s hand. Look to Him.
This is also good news because God has given us the message of the gospel, the ministry of reconciliation. Who is competent for these things? God has entrusted us with this task precisely because we are not competent, in order to show that it all depends on Him—not us. You don’t need to manipulate people into the Kingdom as if your persuasiveness is what matters. You get to openly proclaim the truth in love, stumbling along the way like a toddler learning to walk, then rest knowing that you didn’t change the number of God’s elect. God will save all His elect and He has elected to use clumsy tools like you and I to do it.
God’s sovereignty in man’s salvation does not make Him a scary monster. Rather it is the only way anyone could ever be saved; it is therefore a great source of comfort for those who will look to Christ for salvation.