The saying of Jesus

Jesus

Jesus of Nazareth , commonly referred to as Jesus Christ or simply as Jesus or Christ, is the central figure of Christianity...

concerning his true relatives is found in the Canonical gospels  of Mark

Gospel of Mark

The Gospel According to Mark , commonly shortened to the Gospel of Mark or simply Mark, is the second book of the New Testament. This canonical account of the life of Jesus of Nazareth is one of the three synoptic gospels. It was thought to be an epitome, which accounts for its place as the second...

 and Matthew

Gospel of Matthew

The Gospel According to Matthew is one of the four canonical gospels, one of the three synoptic gospels, and the first book of the New Testament. It tells of the life, ministry, death, and resurrection of Jesus of Nazareth...

.

In the Bible

From :

There came then his brethren and his mother, and, standing
without, sent unto him, calling him.
And the multitude sat about him, and they said unto him,
Behold, thy mother and thy brethren without seek for thee.
And he answered them, saying, Who is my mother, or my
brethren?
And he looked round about on them which sat about him, and
said, Behold my mother and my brethren!
For whosoever shall do the will of God, the same is my
brother, and my sister, and mother.

From :

While he yet talked to the people, behold, his mother and
his brethren stood without, desiring to speak with him.
Then one said unto him, Behold, thy mother and thy brethren
stand without, desiring to speak with thee.
But he answered and said unto him that told him, Who is my
mother? and who are my brethren?
And he stretched forth his hand toward his disciples, and
said, Behold my mother and my brethren!
For whosoever shall do the will of my Father which is in
heaven, the same is my brother, and sister, and mother.

Apocryphal version

A re-organized version also appears in the Gospel of Thomas

Gospel of Thomas

The Gospel According to Thomas, commonly shortened to the Gospel of Thomas, is a well preserved early Christian, non-canonical sayings-gospel discovered near Nag Hammadi, Egypt, in December 1945, in one of a group of books known as the Nag Hammadi library...

 (Patterson-Meyer Translation):

⁹⁹ The disciples said to him, "Your brothers and your mother are
standing outside." He said to them, "Those here who do what my
Father wants are my brothers and my mother. They are the ones who
will enter my Father's kingdom."
¹⁰⁰ They showed Jesus a gold coin and said to him, "The Roman
emperor's people demand taxes from us." He said to them, "Give the
emperor what belongs to the emperor, give God what belongs to God,
and give me what is mine."
¹⁰¹ "Whoever does not hate [father] and mother as I do cannot be
my [disciple], and whoever does [not] love [father and] mother as
I do cannot be my [disciple]. For my mother [...], but my true
[mother] gave me life."

Verse 100 (Caesar's Coin) is similar to Mark 12:13-17 and Luke 20.22-26. Verse 101 (Love Jesus/God more than your family) is similar to and .