"But the LORD said unto Samuel, look not on his countenance, or on the height of his stature; because I have refused him: for the LORD sees not as man sees; for man looketh on the outward appearance, but the LORD looketh on the heart. (1Samuel 16:7)
We Don't Do the Choosing God Does
God sent Samuel on a mission to pick a King from among the sons of Jesse (1 Samuel 16:1). Samuel was a man of prophecy, a chosen vessel by God to speak, and do, what God told him to speak, and do. We, believers in Christ Jesus, are also chosen vessels to speak, and do, what the Lord tells us to speak, and do. God told Samuel that He would do the choosing (1 Samuel 16:3). Samuel started out listening to God but once he got to Bethlehem he started walking in self. I can only guess, because I am not God and cannot read minds, that the site of even the elders trembling made him think of himself as more or better than. Just an assumption. I only know that God didn't give him or any man the omniscient power within himself to choose. Anyway, Samuel decided within himself that he would choose a man that he though, by considering one's outward appearance, to be the best looking most muscular strapping man out of the sons of Jesse. But God didn't ask Samuel, nor does He ask us, to do that. God said that He would choose (1 Samuel 16:3).
Man Looks on the Outside
God is Omniscient, so He sees and knows the heart of man. We don't have the power to do that. We walk by faith, not by sight (2 Corinthians 5:7). We must trust God to Choose. It is a very sad thing to be overlooked because someone believes that you don't fit the profile or rather look the part of how they think that you should look. This happens many times over not only in the world, but in the church, or rather amongst believers, the body of Christ. The uncomely parts of the body are overlooked. This ought not be. In fact, this would happen to Jesus as prophesied by Isaiah (Isaiah 53:2).
God Does the Calling
God is the One Who chooses who He uses. He is the One Who gives to His Son Jesus Christ the person and part that that person will play in His body, and they will not be turned away (John 6:37,44). "And he gave some, apostles; and some, prophets; and some, evangelists; and some, pastors and teachers; for the perfecting of the saints, for the work of the ministry, for the edifying of the body of Christ: (Ephesians 4:11-12).
The gifts and calling of God are to equip and perfect the saints, uniting us in the faith and knowledge of Jesus so that we don't waver or start believing in all types of doctrine other than the Gospel of Jesus Christ (vs 13,14). His calling doesn't require a degree, money, or special economic status. God calls God equips.
So, What Is Your Part?
"For God so loved the world, that he gave his only begotten Son, that whosoever believeth in him should not perish, but have everlasting life (John 3:16). "This is the work of God, that ye believe on him whom he hath sent (John 6:29). That's it. God will tell us what to say and do. When our faith is wholly placed in Jesus, our works will be of God.