When Jacob, who was renamed Israel by God, was on his deathbed he blessed Manasseh and gave him the status as one of his sons.
Manasseh as the first born should have had the double blessing but it went to his younger brother Ephraim when Jacob blessed them and called them as his own sons.
Manasseh in Hebrew means: causing to forget.
Background information read Genesis 48:1-22 - Manasseh and Ephraim
Manasseh and Ephraim
Genesis 48 Some time later Joseph was told, "Your father is ill." So he took his two sons Manasseh and Ephraim along with him. 2 When Jacob was told, "Your son Joseph has come to you," Israel rallied his strength and sat up on the bed.
3 Jacob said to Joseph, "God Almighty appeared to me at Luz in the land of Canaan, and there he blessed me 4 and said to me, ‘I am going to make you fruitful and will increase your numbers. I will make you a community of peoples, and I will give this land as an everlasting possession to your descendants after you.’
5 "Now then, your two sons born to you in Egypt before I came to you here will be reckoned as mine; Ephraim and Manasseh will be mine, just as Reuben and Simeon are mine. 6 Any children born to you after them will be yours; in the territory they inherit they will be reckoned under the names of their brothers. 7 As I was returning from Paddan, to my sorrow Rachel died in the land of Canaan while we were still on the way, a little distance from Ephrath. So I buried her there beside the road to Ephrath" (that is, Bethlehem).
8 When Israel saw the sons of Joseph, he asked, "Who are these?"
9 "They are the sons God has given me here," Joseph said to his father.
Then Israel said, "Bring them to me so I may bless them."
10 Now Israel's eyes were failing because of old age, and he could hardly see. So Joseph brought his sons close to him, and his father kissed them and embraced them.
11 Israel said to Joseph, "I never expected to see your face again, and now God has allowed me to see your children too."
12 Then Joseph removed them from Israel's knees and bowed down with his face to the ground. 13 And Joseph took both of them, Ephraim on his right toward Israel's left hand and Manasseh on his left toward Israel's right hand, and brought them close to him. 14 But Israel reached out his right hand and put it on Ephraim's head, though he was the younger, and crossing his arms, he put his left hand on Manasseh's head, even though Manasseh was the firstborn.
15 Then he blessed Joseph and said,
"May the God before whom my fathers
Abraham and Isaac walked,
the God who has been my shepherd
all my life to this day,
16 the Angel who has delivered me from all harm
—may he bless these boys.
May they be called by my name
and the names of my fathers Abraham and Isaac,
and may they increase greatly
upon the earth."
17 When Joseph saw his father placing his right hand on Ephraim's head he was displeased; so he took hold of his father's hand to move it from Ephraim's head to Manasseh's head. 18 Joseph said to him, "No, my father, this one is the firstborn; put your right hand on his head."
19 But his father refused and said, "I know, my son, I know. He too will become a people, and he too will become great. Nevertheless, his younger brother will be greater than he, and his descendants will become a group of nations." 20 He blessed them that day and said,
"In your name will Israel
pronounce this blessing:
‘May God make you like Ephraim and Manasseh.’"
So he put Ephraim ahead of Manasseh.
21 Then Israel said to Joseph, "I am about to die, but God will be with you and take you back to the land of your fathers. 22 And to you, as one who is over your brothers, I give the ridge of land I took from the Amorites with my sword and my bow."
Jacob Blesses His Sons
Genesis 49 Then Jacob called for his sons and said: "Gather around so I can tell you what will happen to you in days to come.
2 "Assemble and listen, sons of Jacob;
listen to your father Israel.
3 "Reuben, you are my firstborn,
my might, the first sign of my strength,
excelling in honor, excelling in power.
4 Turbulent as the waters, you will no longer excel,
for you went up onto your father's bed,
onto my couch and defiled it.
5 "Simeon and Levi are brothers—
their swords are weapons of violence.
6 Let me not enter their council,
let me not join their assembly,
for they have killed men in their anger
and hamstrung oxen as they pleased.
7 Cursed be their anger, so fierce,
and their fury, so cruel!
I will scatter them in Jacob
and disperse them in Israel.
8 "Judah, your brothers will praise you;
your hand will be on the neck of your enemies;
your father's sons will bow down to you.
9 You are a lion's cub, O Judah;
you return from the prey, my son.
Like a lion he crouches and lies down,
like a lioness—who dares to rouse him?
10 The sceptre will not depart from Judah,
nor the ruler's staff from between his feet,
until he comes to whom it belongs
and the obedience of the nations is his.
11 He will tether his donkey to a vine,
his colt to the choicest branch;
he will wash his garments in wine,
his robes in the blood of grapes.
12 His eyes will be darker than wine,
his teeth whiter than milk.
13 "Zebulun will live by the seashore
and become a haven for ships;
his border will extend toward Sidon.
14 "Issachar is a rawboned donkey
lying down between two saddlebags.
15 When he sees how good is his resting place
and how pleasant is his land,
he will bend his shoulder to the burden
and submit to forced labour.
16 "Dan will
provide justice for his people
as one of the tribes of Israel.
17 Dan will be a serpent by the roadside,
a viper along the path,
that bites the horse's heels
so that its rider tumbles backward.
18 "I look for your deliverance, O LORD.
19 "Gad will
be attacked by a band of raiders,
but he will attack them at their heels.
20 "Asher's food will be rich;
he will provide delicacies fit for a king.
21 "Naphtali is a doe set free
that bears beautiful fawns.
22 "Joseph is a fruitful vine,
a fruitful vine near a spring,
whose branches climb over a wall.
23 With bitterness archers attacked him;
they shot at him with hostility.
24 But his bow remained steady,
his strong arms stayed limber,
because of the hand of the Mighty One of Jacob,
because of the Shepherd, the Rock of Israel,
25 because of your father's God, who helps you,
because of the Almighty, who blesses you
with blessings of the heavens above,
blessings of the deep that lies below,
blessings of the breast and womb.
26 Your father's blessings are greater
than the blessings of the ancient mountains,
than the bounty of the age—old hills.
Let all these rest on the head of Joseph,
on the brow of the prince among his brothers.
27"Benjamin is a ravenous wolf;
in the morning he devours the prey,
in the evening he divides the plunder."
28 All these are the twelve tribes of Israel, and this is what their father said to them when he blessed them, giving each the blessing appropriate to him.
Manasseh, whose name in Hebrew means causing to forget, was the older son of Joseph or his Egyptian name Zaaphnathpaneah which means:- abundance of life and princess Asenath which in Egyptian means:- belonging to Neith.