This was the teaching of the Lord expressly

All that the Father gives me will come to me, and the one who comes to me I will not at all send away. 

For the wages of sin is death; but the gift of God is eternal life in Jesus Christ our Lord. Romans 6:23

“For I came down from heaven, not to do my own will, but the will of him who sent me.  And this is the will of the Father who has sent me, that of all whom he has given me I should lose none, but should raise them up again at the last day. John 6:37-39

No man can come to me unless the Father who has sent me draws him. And I will raise him up at the last day. John 6:44

For what does the Scripture say? Abraham believed God, and it was put to his account as righteousness. Now to him who works his wage is not reckoned as grace, but as something owed.  But to him who does not work but believes in him who justifies the ungodly, that faith is put to his account as righteousness.  Romans 4:3-5

Only let your conduct be worthy of the gospel of Christ, so that whether I come and see you, or be absent, I may hear about you that you are standing firmly in one spirit, with one mind striving together for the faith of the gospel,  and not at all afraid of your opponents. This is a clear sign to them of their destruction, but to you of your salvation, and that of God.  For it has been given to you on behalf of Christ, not only to believe on him, but also to suffer for his sake, Philippians 1:27-29

But as many as received him, to those who believed in his name, to them he gave the right to become the sons of God,  who were born, not of blood, nor of the will of the flesh, nor of the will of man, but of God. John 1:12-13

 (John 6:37, 44, 45, 65) and by implication (3:3-8). It is Paul’s teaching (Rom 8:5-9; Eph 2:8-10; Phil 1:29) and Peter’s (2 Pet 1:1).