I feel like it is important to learn what God has done through Christ and in Christ (there is a difference, I think), and preterists and others rightly point to many of those things.
What God has freely done by grace (undeserved Love) does not entail that all people are ‘saved’ or filled with the Spirit - obviously - and if they are not, they are not ‘sons of God’ in that sense. We who lived in the 20th century know for certain what happens when people are not led by the Holy Spirit, yes?
“All this is from God, who through Christ reconciled us to himself and gave us the ministry of reconciliation; that is, in Christ God was reconciling the world to himself, not counting their trespasses against them, and entrusting to us the message of reconciliation. Therefore, we are ambassadors for Christ, God making his appeal through us. We implore you on behalf of Christ, be reconciled to God. For our sake he made him to be sin who knew no sin, so that in him we might become the righteousness of God.”
That portion I bolded points to what the job of Christ’s ambassadors IS. To show by our lives, preaching, anyway we can, what God has done in Christ and imploring people TO BE reconciled - that is, they have to do something. If they don’t, then they have not reconciled themselves to God, even though God has reconciled the world to Himself.
That imploring reaches to us today.