26 To [pros] declare [endeixis], I say, at [en] this [nun] time [kairos] his [autos] righteousness [dikaiosune]:
that [eis] he might be [einai] just [dikaios], and [kai] the justifier [dikaioo] of
him [autos] which believeth [pistis] in [ek] Jesus [Iesous]. KJV-Interlinear
26 It was
to show his righteousness at the present time, so that he might be just and the
justifier of the one who has faith in Jesus. ESV
No pardon or forgiveness could be given until the penalty for sin had been paid. And thus it was not until the Cross when Christ paid the penalty for sin, by enduring the punishment for sin, in our place, was God able to offer salvation and thus forgive to anyone who accepted His work in their place.
At this time, is the reference to the current time of Jesus and the event of the Cross.
Now the Law, or the Mosaic Law, was the standard by which no person could live. Anyone who could not live by it, was of course condemned. And since no person can live the perfect life demanded by the Law, then all are condemned. Any little infraction, no matter how small, was sufficient for guilt.
Adam took a simple bite from the forbidden fruit. God forbade it, but Adam violated that rule. And obviously we have all cross the line at some point in our life, and certainly many times, so by our own thoughts and actions, we condemn ourselves, not to mention that we are the product of sin, simply be being a descendant of Adam.
And as a result of our infraction, no person can escape judgment, until the penalty has been paid. Thus, no person in the Old Testament could go to heaven until after the Cross had been accomplished. And once accomplished, then all were free and no longer bound by the sentence of sin. It had been served.
So, God is righteous. God is just. And God is the justifier. No one else can fulfill that role, nor have that authority.
And, we have but only to look at Him and His plan and His effort and believe.
There is nothing more to do. We can do nothing more. To try to do more or to do anything of our own, says that we reject God, reject Jesus Christ, and reject His effort, because we believe that we need to do something that He did not. And only a fool would think that way.