Midrash su Isaia 51:2

Her children rise up, and call her blessed (Prov. 31:28); And she said: Who would have said unto Abraham that Sarah should give children suck? For I have born him a son in his old age (Gen. 21:7). Many daughters have done valiantly (Prov. 31:29) refers to the nations, But thou excellest them all (ibid.) alludes to Sarah, as it is said: Look unto Abraham, your father, and to Sarah, that bore you (Isa. 51:2). Give her of the fruit of her hand (Prov. 31:31), for it is said: And the life of Sarah was a hundred and twenty and seven years (Gen. 23:1).

It is written that after Sarah’s death, the Holy One, blessed be He, blessed Abraham. Why did He do that? Lest future generations declare that Abraham was blessed only because of Sarah. (And so He said to Himself:) I will bless him after her death. Hence it is written: And the Lord had blessed Abraham. Whence do we know that Sarah was already dead when He blessed him? It is said: When he was but one, I called him, and I blessed him (Isa. 51:2). And the Lord blessed Abraham in all things (Gen. 24:1). What merit had he acquired? He set aside tithes from all his possessions, as it is said: And He gave him a tenth of all (Gen. 14:20).⁶The law of tithes requires that a tenth part of one’s earnings be set aside for charitable purposes. See Jewish Encyclopedia 12:150. Hence it is written: And the Lord blessed Abraham in all things.

That saith of Jerusalem: “She shall be inhabited”; and of the cities of Judah; “They shall be built” relates to the subject we are discussing. Though the nations were confident that Jerusalem would not be rebuilt, it will be rebuilt, as it is said: That saith of Jerusalem: “She shall be inhabited”, and it is written elsewhere: When the Lord hath built Zion (Ps. 102:17). But if you are doubtful as to the ultimate rebuilding of Jerusalem, look unto Abraham, your father, and unto Sarah who bore you (Isa. 51:2), for just as I did in behalf of Sarah and Abraham, so I shall do in behalf of Jerusalem.