Ereō serves as the future tense of legō — 'I will say' or 'it will be said.' It is a defective verb, supplying the future forms that legō lacks. It appears in contexts where someone will speak a future word — often in eschatological judgment contexts. Matthew 7:22 uses it: 'Many will say [erousin] to me on that day...' It also appears in prophetic declarations: Romans 9:12 quotes Genesis — 'it was said to her.'
Ereō in its most chilling use is Matthew 7:23 — 'Then I will tell [erō] them plainly: I never knew you.' The future divine speech of judgment. This word, positioned as the sovereign declaration of the returning Christ, cuts through all religious activity and performance to the question of genuine relationship: 'Did I know you?' The comfort of ereō comes in Romans 9:25-26 — God's future word of inclusion: 'I will call them my people... it will be said to them, ‘sons of the living God.’ The same future word that excludes the self-righteous welcomes the formerly rejected.