Paul prefaces in Hebrews 10:37-39 the “Faith Chapter”, Hebrews 11 with quotations from two verses from the Greek translation of the Hebrew Scriptures. All commentators and annotated Bibles note the quote from Habakkuk 2:3b-4 but only a small percentage note the quote from Isaiah 26:20. The linkage of the two verses from Habakkuk and Isaiah by Paul follows one of 
Hillel’s principles, binyan av mishnai katuvim, broadening the understanding of both verses.
Hebrews 10:37-11:6a is a Midrash of the Source Text Genesis 38:27-41:38. Paul’s Midrash here is of the birth of Perez and Zerah by Tamar and Judah. You may recall Zerah stuck his hand out first and the midwife tied a scarlet thread around his wrist for future identification. (A similar event occurred when Rahab hung a scarlet cord out her window for future identification.) Paul’s use of the word “shrinks back” is an allusion to Zerah pulling his hand back into the womb. The word “shrinks back”, a verb in Hebrews 10:38, within the quote of Habakkuk 2:4 from the LXX has its first use in Exodus 23:21 regarding the LORD’s instruction to Moses that the Angel of the LORD would be before them and would guard them in the way to bring them into the land God had promised them:
Take heed to yourself, and hearken to him, and do not resist his persuasion, for he should not avoid you, for my name is upon him!
The very closely related noun “shrink back” in Hebrews 10:39 is a hapax legomenon with no other use in the LXX or the New Testament showing just how unique it would be to ‘shrink back’ or ‘resist the persuasion’ of the Messiah. The word “saving” in Hebrews 10:39 has its first use in the LXX in 2 Chronicles 14:13 within the context of Zarah the Ethiopian with a force of a million and 300 chariots deployed war against King Asa of Judah who called on the LORD God for deliverance.
There are five men named Zerah in the Tanakh. Rather than using a usual word for ‘saving’ in Hebrews 10:39, building a commentary on Zerah Paul used a word with its first use in the context of another Zerah. Redundancy is a literary device termed pleonasm. This is a suppressed pleonasm not previously described and only discovered through Midrash.
There are three unusual facts about Zerah the son of Tamar. First, he was marked for further identification with a scarlet thread. Second, the meaning of his name is not mentioned at his birth like most others in the book of Genesis. Third, he is the only person listed by name in the genealogy of Yeshua the Messiah but not in his lineage. (Matthew 1:3) His name means “a rising”. Those that have believed in the Messiah are in his genealogy. The brothers and sisters of Messiah are the ones that have taken his name, his lineage and are marked with the scarlet of his blood and at our ‘rising’ we will not shrink back to the destruction we will leave behind!
These three verses are the preface of the “Faith Chapter” which is built around the faithfulness (Genesis 42:20) of the sons of Israel to return to their brother Joseph, a foreshadowing of the Messiah. In the “faith Chapter” Midrash and the Source Text within Genesis there are 31 allusions to the Rapture!