Why did Jacob give more prominent blessings to Joseph and judah?

Joseph (Jacobs first son) was the son of rachel. Jacob loved rachel more than his other wife Leah. Josheph was Jacobs favorite son. leahs sons were jealous of Joseph so they sold him into slavery and Jacob thought that he was dead. because the sons brought back his coat after they smeared blood all over it.

Answer:

The "blessing" or "birthright" [the custom of the father to pass his possessions on to, generally, his firstborn son - see I Chronicles 5:1], was seldom done throughout the account of Abraham and his descendants.

Abraham's "possessions" were the Promises of God or "covenant" with him. This was a "dual" promise -- one of material, earthly wealth and national prosperity; and the other of a "spiritual" nature: a "blessing" or "salvation" in which "all the families of the earth shall be blessed," which is the promise of the Messiah. Theses two promises stayed linked together as one promise for two generations... and were passed down together and became the possession of Abraham's sons, Isaac and Jacob.

Abraham's firstborn was Ishmael... but Isaac got the "blessing."

Isaac's firstborn was Esau... but Jacob the younger son got the blessing.

Jacob's firstborn was Reuben... but Joseph [as explained in I Chron.5 and the answer above]... received the promise or "blessing" of "MATERIAL PROSPERITY."

Here is where the two promises of God to Abraham became separated.

Judah the first "Jew" received the "blessing" of... uh... "blessing" or "the Christ" as Jacob on his deathbed ran down his list of sons, giving each their "inheritance" as he went. Judah got the "blessing" of the Christ -- Gen.49:8-12.

Meanwhile... back in Genesis 48... Jacob [Israel], in blessing Joseph with the material promise, did it through his two sons who were born to him in Egyptian captivity. And in doing so... the promise of material prosperity itself became split in two... and pronounced as a "shared blessing" on Joseph's two sons. Of which, THE YOUNGER SON, EPHRAIM, was blessed above his elder brother, Manasseh, somehow in keeping with the family's turbulent history of the passing down of the Abrahmic birthright blessing.

As for "why" it happened that way... one might chalk it down to the machinations of human intrigue and manipulation of motherhood (?). Because whether or not it was "right" or "wrong" the way it turned out... God accepted it as it played out... and blessed each recipient of the birthright promise, accordingly.

Isaac's mother was jealous of Hagar and Ishmael and had them banished, thus removing Ishmael from the mix.

Jacob's mother "liked him best"... and helped him achieve the blessing above Esau.

Jacob, though he was blind, we are told passed the blessing to Ephraim "knowingly"... knowing he was the younger. His motive isn't disclosed in scripture. Who is to say, that in keeping with the historical record, perhaps he was having a little fun -- and wanted to keep the screwed up birthright record on its twisted track.