1 Samuel 17:26-29 Then David spoke to the men who stood by him, saying, "What shall be done for the man who kills this Philistine and takes away the reproach from Israel? For who is this uncircumcised Philistine, that he should defy the armies of the living God?" And the people answered him in this manner, saying, "So shall it be done for the man who kills him." Now Eliab his oldest brother heard when he spoke to the men; and Eliab's anger was aroused against David, and he said, "Why did you come down here? And with whom have you left those few sheep in the wilderness? I know your pride and the insolence of your heart, for you have come down to see the battle." And David said, "What have I done now? Is there not a cause?"
David's faith and courage in volunteering to fight Goliath were an embarrassment to his big brother Eliab, an officer in King Saul's army. I imagine his thinking went something like this; “If my little brother wins everybody will ask, 'How come you didn't go out and fight him?'” The Bible records that Eliab “burned with anger at David and asked, 'Why have you come down here? And with whom did you leave those few sheep in the desert? I know how conceited you are and how wicked your heart is...'” These are devastating words from an older brother. Before David could defeat Goliath he first had to overcome the attitudes, accusations, and words, of those close around him.
The defeat of Goliath had massive implications for Israel and for the Lord. Satan had staked a great deal on Goliath's terrifying power. So wherever the enemy had an opportunity in the sinful attitudes of David's friends and family he maximized them, realizing that David truly had the anointing of God to turn the tide of battle. And God allowed David to be tested by his own closest kin.
If there is a true Goliath in your life and you are appointed to slay him be assured you will face similar tests from those close by. When you make decisions to step out and follow God it will put pressure on others to do the same. Their shame and lack of faith will move them to attack, belittle and criticize you. It will come from among those closest to you, especially if your calling sets you apart!
Be careful around those who say, “I knew you when...” in an attempt to label, libel, or limit you – much like David's brother Eliab tried to hinder him. David was empowered by the Lord to slay Goliath – if you have that same Spirit and calling then humbly step aside and say, "What have I done now? Isn't there a real job to be done?" Then go ahead, and do it.