In Romans 8, we have an important example of the first class conditional sentence. It says,
“What then shall we say to these things? If God is for us, who is against us?” – Rom. 8:31
In some conditional sentences it is uncertain if the condition will be met (examples of conditions of third class include Matthew 6:14 and Luke 17:3,4 where it is not certain if man will do the right thing, and thus the blessing is uncertain), but in the first class conditional sentence there is no uncertainty. Daniel B. Wallace offers the following definition:
“The first class condition indicates the assumption of truth for the sake of argument. The normal idea, then, is if–and let us assume that this is true for the sake of argument–then . . . .”1
In it the particle ei is used and the idea is not “if” God is for us, but “since” God is for us, who can be against us. The statement by the Apostle answers the doubts of Christians who wonder if they can endure all things. Paul wants the Christian to know there is no doubt that God is for them. Consequently, no one can be against them because God loves His children and it doesn’t matter who is against them. No angel or any other created thing is able to separate us from the love of God. Paul writes,
“He who did not spare His own Son, but delivered Him over for us all, how will He not also with Him freely give us all things?”
Who can doubt that God is for us!
Wallace, Daniel B. Greek Grammar: Beyond the Basics. p. 690)