Creed (basic tenets of faith) of early church: four points each introduced with the word "that":
Paul invites everyone to inquire for themselves the authenticity of resurrection.
Paul considers his experience not a visionary experience but an actual resurrection experience.
Paul again argues that he is an apostle, but at the same time chief of sinners (1Ti 1:15).
God's gracious gift of apostleship was a divine initiative; Paul's response is his hard work. Despit his hard work, his emphasis is that nothing of God's grace is deserved.
If there is no resurrection, his preaching will then be a lie; even more seriously, Paul and others would be false witnesses about what God did and false witness in God's name.
Their faith is futile because: to themselves (the living), they are still in sin; to those believers who died, there is no future and they have died in their sins.
They would be most pitied because they have lost their future as well as their past and present.
firstfruits = the first of the harvest serving as a kind of guarantee for the full harvest (like the down payment of the Holy Spirit, 2Co 1:22, Eph 1:14); resurrection of the believing dead is absolutely inevitable because it has been guaranteed by God himself.
Christ stands at the beginning of the new humanity in a way analogous to, but not identical with, the way Adam stood at the beginning of the old order.
Death is inevitable because human beings share in the humanity and sinfulness of Adam. Similary, resurrection is inevitable as believers receive salvation in Christ.
Events in order: (a) resurrection of Christ; (b) resurrection of believers at the coming of Christ; (c) destruction of the enemy: dominion, authority and power (spiritual malevolent demonic powers, Eph 1:21; Ro 8:38; Col 1:16; 2:10,15; Eph 3:10; 6:12)
Christ reigns presently de jure (by right, in principle), ultimately de facto (in fact).
God will place all things under Christ, including his enemies and death (Ps 110:1, 8:6).
Problem with "baptism for (in behalf of) the dead": at least 40 solutions, none definitive. Possibly, the Corinthians believed baptism to be necessary for entering God's kingdom so some believers were baptized for others who were believers when they died but had never been baptized (a form of vicarious baptism).
Paul's noncommittal attitude toward it cannot be used to mean approval for such practice.
On a daily basis Paul faces the reality of death. Paul is indeed crazy to put his life in constant jeopardy for the sake of others, if neither he nor they have hope in resurrection.
Paul is in Ephesus at that time. In 16:9 he refers to many who oppose him there; "fighting with wild beasts" is probably metaphorical, referring to that struggle, involving also physical danger.
The citation is from Is 22:13; this philosophy is attributed to the Epicureans, a formula for life with loose moral and conduct.
Keeping company with evil companions can have a corrosive influence on one's own attitudes and behaviour; "company" can mean conversation, evil conversation denying resurrection.
Those who deny the resurrection ultimately live in ignorance of God. They are the same ones with sinful behaviour. This verse points to a genuine relationship between what one believes about the future and how one behaves in the present.