No, God has not disowned His people, on whom He set His heart beforehand. Do you know what the Scripture says in Elijah's case, how he pleaded with God against Israel?

for the ruler is Gods servant to thee for good. But if thou doest evil, be afraid; for he beareth not the sword in vain; for he is Gods servant, an avenger to inflict wrath upon him that doeth evil.

“There is none who understands,
There is none who seeks for God.

the faithfulness of God of no effect? by no means; yea, let God be acknowledged to be true, tho' men should be all deceivers; as it is written, " that you might be justified in your sayings, and might overcome when you are judged."

because they changed the true God for false gods, and adored and worshipped created things rather than the Creator, who is blessed for ever. Amen.

Behold then the goodness and the severity of God; toward those who fell, severity; but toward thee Gods goodness, if thou continue in his goodness; otherwise thou also wilt be cut off.

And if by grace, then is it no more of works: otherwise grace is no more grace. But if it be of works, then is it no more grace: otherwise work is no more work.