Posted here by Diana Gale Matthiesen, who reformatted the text, boldfaced the names, and added a summary and comments.

Testator:  Edward CORBIN, Sr., of Baltimore Co., MD
Legatees—
    Wife:  Mary
    Children:  John, Edward, Eliakim, Rachel, Leah, and Mary
Date Signed:  14 Jul 1770
Date Proved:  30 Nov 1770
Where recorded:  Baltimore Co., MD [currently stored Maryland State Archives]
Witnesses:  Thos. HALE; George HARRYMAN, Jr.; Joseph SYARS

First of all I Give and Bequeath unto my loveing Wife Mary Corbin all my Household goods and furniture likewise my dwelling Plantation During her Life if she remains a widow 

also I Give and Bequeath my son Eliakim the sum of Ten pounds current money of this Government or Effect to the value of so much 

also I Give and Bequeath unto Daughter Mary ten pounds currt money aforesd or effects to the value of so much. 

also I Give and bequeath unto my son John five pounds current money aforesd in Effects  to the value of so much 

also I Give and bequeath unto my son Edward Five pounds current money aforsd or effects to the value of so much to come out of my Personal Estate after the Decease of my wife. 

and after the Legacies are paid the remainder of my personal Estate I Give and bequeath to my youngest son Eliakim and my three Daughters Rachel, Leah and Mary to be equally Divided amongst them after paying my Just and Lawfull debts and after the decease of my wife. 

I Give and bequeath unto my son Edward my Dwelling plantation being the half of the fourth part of a Tract of Land called Cumberland to have and to hold to him his Heirs to the proper use and behoof of him the said Edward Corbin and his Heirs and assigns forever. 

also I Give and Bequeath unto my son John 50 acres of Land lying upon Turkey branch called Rochester and if my son John does not get the aforesd Land my will and Desire is that my son Edward and heirs shall have the Dwelling Plantation valued and Divided Equally between them

and I do hereby nominate and appoint my Loveing Wife Mary Corbin of this my Last will and Testament hereby revoking all former will and wills by me heretofore made. In witness whereof I have hereunto set my hand and seal this 14 day of July 1770. 

Edwd. [his mark] Corbin {seal}

The mentioned will on the other side was signed sealed and declared by the above named Edwd. Corbin Senr for his last will and Testament in the presence of us who have hereunto subscribed our names as witnesses thereto in the presence of the said Testator and in the presence of each other. 

Thos. Hale
George Harryman
Joseph [his mark] Lyons [Syons?]

Novr 30th 1770 Came Thomas Hale and made oath that he saw the Testator Edwin (sic) Corbin sign seal publish pronounce and declare the foregoing Instrument as and for his last will and Testament by makeing his mark or scrawl & at the same Time came George Harryman the younger and made oath as afsd that he heard the Testator Acknowledge the forgoing instrument of writeing as and for his last Will and Testament that he saw Joseph Syons [Lyons?] make his mark as an Evidence to the sd will all in the presence of the sd Testator and at his request. 

Sworn to before W. Young Dep. Com'y Balt. County.

George HARRYMAN, Jr. was Edward's first cousin. 

Edwards's nephew, Benjamin CORBIN (s/o Nicholas & Eleanor), married a woman named Sarah SIAS, which surname is variously rendered SIAS, SYAS, SYARS, SIERS, SEARS, etc. (pronounce "SEARS" with a strong British or Southern accent, and you can see the reason for the different phonetic spellings).  Almost certainly, the witness, Joseph LYONS?/SYONS?, is Sarah (SIAS) CORBIN's brother, Joseph SIAS/SYARS. 

As for Thomas HALE, he may be Thomas HALL, who married Ann GREEN, who may have been related to Robert GREEN, who married Unity CORBIN, Edward's sister.  (I know, it's a stretch, but it's the best I could do.)