That we may know it's by His hand and not by accident. Part 1- He chooses the youngest, weakest, least likely to lead HIs people.

I've been noticing this theme throughout the Bible, from beginning to end, that God uses the least likely so that He will get all the glory.  Paul calls himself the "chief of sinners" acknowledging that anything he's accomplished comes by the work of God who "works in him mightily".

Just for fun I thought I'd list how many times the Lord chooses to bless or use the younger son over the older son.  Remember this runs contrary to the culture of primogeniture prevalent in Bible times.

1.  Seth over Cain (Genesis 5)

2.  Abraham not Nahor or Haran (Not definite, but seems to be the case from Gen 11:32, 12:4, Acts 7:2-4 and Genesis 11:26 taken together.  Apparently, Terah began having children at 70 and Abraham was 75 when he left Haran after his father died at age 205.  So, Terah began having kids at 70, but had Abraham when he was 145.)

3.  Isaac over Ishmael (Genesis 21)

4.  Jacob over Esau (Genesis 27)

5.  Joseph over Reuben (1 Chronicles 5:1)

6.  Ephraim over Manasseh (Genesis 48)

7.  Moses over Aaron (not that Aaron wasn't significant, but the Lord chose to use Moses, the younger son,  to deliver His people).

8. Gideon (Lesser tribe of Manasseh, weakest clan in tribe, least in father's house, but chosen to deliver Israel.  Judges 6:15)

9.  Jephthah (Illegitimate son of his father and a prostitute, driven out of his father's house and inheritance by his half-brothers, but chosen by God to deliver Israel.  Judges 11)

10. David was the 7th or 8th son of Jesse (1 Samuel 16:10-11 and 17:12-15, 1 Chronicles 2:13-15)

11. Solomon over Amnon, Daniel, Absalom (killed), or Adonijah (David's 4th son who later contested Solomon's kingship 1 Kings 1). 

Interesting, isn't it?  Why did God do this?  Why did He choose men to lead His people contrary to the world system for choosing leaders?

Let's hear it from the mouth of God.

In the case of Gideon:  "Please, Lord, how can I save Israel?"  Behold, my clan is the weakest in Manasseh, and I am the least in my father's house."  And the Lord said to him, "But I will be with you, and you shall strike the Midianites as one man."  (Judges 6:16)

Spoken to Zerubbabel:  "Not by might, nor by power, but by my Spirit, says the Lord of hosts."  (Zechariah 4:6)

"For consider your calling, brothers:  not many of you were wise according to worldly standards, not many were powerful, not many were of noble birth.  But God chose what is foolish in the world to shame the wise; God chose what is weak in the world to shame the strong; God chose what is low and despised in the world, even things that are not, to bring to nothing things that are, so that no human being might boast in the presence of God."  (1 Corinthians 1:26-29)

Paul further said of his thorn in the flesh:  "Three times I pleaded with the Lord about this, that it should leave me.  But He said to me, 'My grace is sufficient for you, for My power is made perfect in weakness.'  Therefore I will boast all the more gladly of my weaknesses, so that the power of Christ may rest upon me."  (2 Corinthians 12:9)

So the Lord wants to magnify Himself and chooses those least likely to be able to lead on their own.  This way the focus and the credit goes to God. 

"So I will show my greatness and my holiness and make myself known in the eyes of many nations.  Then they will know that I am the Lord."  (Ezekial 38:23)