The concept of common grace can be inferred from a number of Scripture texts.
At the end of Genesis 3, God pronounces judgment on the serpent, Eve, and Adam for their sin. The judgment for Adam and Eve was a curse that affected the blessing of Genesis 1:26-28. Yet the curse did not remove the blessing entirely. A great deal of that blessing remains for all human, svaed or lost. In addition, the penalty of death was not enacted on the outer man immediately. Instead it was delayed by many years.
This same pattern is seen in the Noahic Covenant. Precisely because man is sinful from his infancy (Gen. 8:20), God institutes a covenant that binds him to not destroy earth with a Flood ever again and to preserve regular days and seasons until the end. Apart from the covenant, God would have been just to send one Flood after another upon sinful humanity. This the Noahic covenant is gracious. Since it is made with all of creation, it is also common.
God waited to bring the judgment of the Flood upon the earth to give sinners time to repent (1 Peter 3:20), and after the Flood God deferred judgment on sinners, also giving them a chance to repent (Acts 17:30).
Isaiah 28:23-29 teaches that by God’s common grace both the saved and lost can develop the intellectual and practical skills to succeed at their vocations. God enables people to understand the world as he created in it and to succeed in living in it.
Jesus teaches in Matthew 5:44-45 that the Father shows love toward his enemies (grace) by giving sunshine and rain to both the righteous and the unrighteous alike (common).
Paul also points to the rains and the provision of food as the goodness of God shown to pagan people (Acts 14:17). In addition Paul indicates that this goodness was a witness to God himself (suppressed according to Romans 1).