Matthew 7:14

But strait is the gate, and narrow is the way, which leadeth unto life, and few there be that find it.

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.

Proverbs 4:26-27

Ponder the path of thy feet: so shall all thy ways be sure.

Proverbs 8:20

I walk in the way of righteousness, and in the street of judgment:

Isaiah 30:21

and thine ears hearken to his word that cryeth after thee and sayeth, "This is the way. Walk ye in it. Turn not aside; neither to the righthand nor to the left."

Isaiah 35:8

There shall be foot paths and common streets: this shall be called the holy way. No unclean person shall go through it, for the LORD himself shall go with them that way, and the ignorant shall not err.

Isaiah 57:14

And therefore thus he sayeth, "Make ready, make ready, and clean the street, take up what ye can out of the way that leadeth to my people."

Jeremiah 6:16

Thus sayeth the LORD, "Go into the streets, consider and make inquisition for the old way: and if it be the good and right way, then go therein, that ye may find rest for your souls. But they say, 'We will not walk therein.'

Matthew 16:24-25

Jesus then said to his disciples. "If any man will follow me, let him forsake himself, and take up his cross and follow me.

Matthew 20:16

So the last shall be first, and the first shall be last. For many are called, and few be chosen."

Matthew 22:14

For many are called and few be chosen.

Matthew 25:1-12

Then the kingdom of heaven shall be likened unto ten virgins, which took their lamps, and went to meet the bridegroom:

Mark 8:34

And he called the people unto him, with his disciples also, and said unto them, "Whosoever will follow me, let him deny himself, and take up his cross, and follow me.

Luke 12:32

Fear not little flock, for it is your father's pleasure, to give you a kingdom.

Luke 13:23-30

Then said one unto him, "Lord, are there few that shall be saved?" And he said unto them,

John 15:18-20

"If the world hate you, ye know that he hated me before he hated you.

John 16:2

They shall excommunicate you: yea the time shall come, that whosoever killeth you, will think that he doth God true service.

John 16:33

These words have I spoken unto you that in me ye might have peace. For in the world shall ye have tribulation: but be of good cheer, I have overcome the world."

Romans 9:27-29

But Isaiah crieth concerning Israel, "Though the number of the children of Israel be as the sand of the sea, yet shall a remnant be saved.

Romans 9:32

And wherefore? Because they sought it not by faith: but as it were, by the works of the law. For they have stumbled at the stumbling stone.

Romans 11:5-6

Even so at this time is there a remnant left through the election of grace.

Romans 12:2

And fashion not yourselves like unto this world: But be changed through the renewing of your mind, that ye may prove what thing that good, that acceptable, and perfect will of God is.

Ephesians 2:2-3

in the which, in time past, ye walked, according to the course of this world, and after the governor that ruleth in the air, the spirit that now worketh in the children of unbelief,

1 Thessalonians 3:2-5

and sent Timothy our brother and minister of God, and our labour fellow in the gospel of Christ, to establish you, and to comfort you over your faith,

1 Peter 3:20-21

which were in time past disobedient, when the long suffering of God abode exceeding patiently in the days of Noah, while the ark was a preparing, wherein few - that is to say eight souls - were saved by water,

Treasury of Scripture Knowledge

Summary

Because strait is the gate, and narrow is the way, which leadeth unto life, and few there be that find it.

Bible References

Because

Matthew 16:24
Jesus then said to his disciples. "If any man will follow me, let him forsake himself, and take up his cross and follow me.
Proverbs 4:26
Ponder the path of thy feet: so shall all thy ways be sure.
Proverbs 8:20
I walk in the way of righteousness, and in the street of judgment:
Isaiah 30:21
and thine ears hearken to his word that cryeth after thee and sayeth, "This is the way. Walk ye in it. Turn not aside; neither to the righthand nor to the left."
Isaiah 35:8
There shall be foot paths and common streets: this shall be called the holy way. No unclean person shall go through it, for the LORD himself shall go with them that way, and the ignorant shall not err.
Isaiah 57:14
And therefore thus he sayeth, "Make ready, make ready, and clean the street, take up what ye can out of the way that leadeth to my people."
Jeremiah 6:16
Thus sayeth the LORD, "Go into the streets, consider and make inquisition for the old way: and if it be the good and right way, then go therein, that ye may find rest for your souls. But they say, 'We will not walk therein.'
Mark 8:34
And he called the people unto him, with his disciples also, and said unto them, "Whosoever will follow me, let him deny himself, and take up his cross, and follow me.
John 15:18
"If the world hate you, ye know that he hated me before he hated you.
John 16:2
They shall excommunicate you: yea the time shall come, that whosoever killeth you, will think that he doth God true service.
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.
1 Thessalonians 3:2
and sent Timothy our brother and minister of God, and our labour fellow in the gospel of Christ, to establish you, and to comfort you over your faith,

General references

Numbers 4:48
was eight thousand, five hundred and eighty,
Proverbs 2:9
Then shalt thou understand righteousness, judgment and equity - yea, and every good path.
Proverbs 14:12
There is a way which some men think to be right; but the end thereof leadeth unto death.
Matthew 22:14
For many are called and few be chosen.
Romans 3:17
And the way of peace have they not known."