Matthew 18:3

and said, "Verily, I say unto you, Except ye turn, and become as children, ye cannot enter into the kingdom of heaven.

Mark 10:14-15

When Jesus saw that, he was displeased, and said to them, "Suffer the children to come unto me and forbid them not. For of such is the kingdom of God.

1 Peter 2:2

and as newborn babes desire that reasonable milk which is without corruption, that ye may be grown therein.

1 Corinthians 14:20

Brethren, be not children in wit. Howbeit, as concerning maliciousness be children: but in wit be perfect.

Matthew 19:14

But Jesus said unto them, "Suffer the children, and forbid them not to come to me, for of such is the kingdom of heaven."

Psalm 131:2

But I refrain my soul and keep it low, like as a child that is weaned from his mother; Yea, my soul is even as a weaned child.

Matthew 5:20

For I say unto you, Except your righteousness exceed the righteousness of the Scribes and Pharisees, ye cannot enter into the kingdom of heaven.

Luke 18:16-17

But Jesus called them unto him, and said, "Suffer children to come unto me, and forbid them not. For of such is the kingdom of God.

Luke 22:32

But I have prayed for thee that thy faith fail not. And when thou art converted, strengthen thy brethren."

Psalm 51:10-13

Make in me a clean heart, O God, and renew a right spirit within me.

Isaiah 6:10

Harden the heart of this people, stop their ears, and shut their eyes, that they see not with their eyes, hear not with their ears, and understand not with their heart, and convert and be healed."

Matthew 5:18

For truly I say unto you, till heaven and earth perish, one jot or one tittle of the law shall not escape till all be fulfilled.

Matthew 6:2

Whensoever therefore thou givest thine alms, thou shalt not make a trumpet to be blown before thee, as the hypocrites do in the synagogues, and in the streets, for to be praised of men. Verily I say unto you, they have their reward.

Matthew 6:5

And when thou prayest, thou shalt not be as the hypocrites are: for they love to stand and pray in the synagogues, and in the corners of the streets, because they would be seen of men. Verily I say unto you, they have their reward.

Matthew 6:16

"Moreover, when ye fast, be not sad as the hypocrites are: for they disfigure their faces, that they might be seen of men how they fast. Verily I say unto you, they have their reward.

Matthew 13:15

For this people's hearts are waxed gross. And their ears were dull of hearing, and their eyes have they closed, lest they should see with their eyes, and hear with their ears, and should understand with their hearts, and should turn, that I might heal them.

Matthew 19:23

Then Jesus said then unto his disciples: "Verily I say unto you, it is hard for a rich man to enter into the kingdom of heaven.

Mark 4:12

that when they see, they shall see, and not discern: and when they hear they shall hear, and not understand: lest at any time they should turn, and their sins should be forgiven them."

Luke 13:24

"Strive with yourselves to enter in at the strait gate: For many, I say unto you, will seek to enter in, and shall not be able.

John 1:51

And he said unto him, "Verily, verily, I say unto you, Hereafter shall ye see heaven open, and the angels of God ascending, and descending over the son of man."

John 3:3

Jesus answered, and said unto him, "Verily, verily I say unto thee: except a man be born anew, he cannot see the kingdom of God."

John 3:5

Jesus answered, "Verily, verily I say unto thee: Except that a man be born of water, and of the spirit, he cannot enter into the kingdom of God.

Acts 3:19

Repent ye, therefore, and turn: that your sins may be done away when the time of refreshing cometh, which we shall have of the presence of the Lord,

Acts 14:22

and strengthened the disciples souls: exhorting them to continue in the faith, affirming that we must through much tribulation enter into the kingdom of God.

Acts 28:27

For the heart of this people is waxed gross, and their ears were thick of hearing, and their eyes have they closed, lest they should see with their eyes, and hear with their ears, and understand with their hearts, and should be converted, and I should heal them.'

James 5:19-20

Brethren if any of you err from the truth, and another convert him,

2 Peter 1:11

Yea, and by this means an entering-in shall be ministered unto you abundantly into the everlasting kingdom of our Lord and saviour Jesus Christ.

Treasury of Scripture Knowledge

Summary

And said, Verily I say unto you, Except ye be converted, and become as little children, ye shall not enter into the kingdom of heaven.

Bible References

And become

Mark 10:14
When Jesus saw that, he was displeased, and said to them, "Suffer the children to come unto me and forbid them not. For of such is the kingdom of God.
Luke 18:16
But Jesus called them unto him, and said, "Suffer children to come unto me, and forbid them not. For of such is the kingdom of God.
1 Corinthians 14:20
Brethren, be not children in wit. Howbeit, as concerning maliciousness be children: but in wit be perfect.
1 Peter 2:2
and as newborn babes desire that reasonable milk which is without corruption, that ye may be grown therein.

General references

Mark 10:15
Verily I say to you, whosoever shall not receive the kingdom of God as a child, he shall not enter therein."
Luke 9:46
Then there arose a disputation among them: who should be the greatest.
Luke 22:26
But ye shall not be so. But he that is greatest among you, shall be as the youngest: And he that is chief, shall be as the minister.
Acts 8:19
"Give me also this power, that on whomsoever I put the hands, he may receive the holy ghost."