James 4:6 But he giveth more grace. Wherefore he saith, God resisteth the proud, but giveth grace unto the humble.

This verse is a paraphrase of Proverbs 3:34:

Proverbs 3:34 Surely he scorneth the scorners: but he giveth grace unto the lowly.

Pride, often manifested in scorn, will cause God to resist (oppose) us.  Pride is what caused Satan to be cast out of heaven (Isaiah 14:12-15).  Pride is one of the seven deadly sins (Proverbs 6:16-19).  If we desire God’s grace on our lives, we must be humble.  In short, we must resist pride or God will resist us.  

Although it does not make sense to our fallen minds, it is humility that brings exaltation.

James 4:10 Humble yourselves in the sight of the Lord, and he shall lift you up.

This is true of many throughout the Bible including Joseph, Moses, Ruth, Daniel, and Esther.  The greatest example humility bringing exaltation is Jesus Christ.

Philippians 2:5-11 Let this mind be in you, which was also in Christ Jesus: 6 Who, being in the form of God, thought it not robbery to be equal with God: 7 But made himself of no reputation, and took upon him the form of a servant, and was made in the likeness of men: 8 And being found in fashion as a man, he humbled himself, and became obedient unto death, even the death of the cross.  9  Wherefore God also hath highly exalted him, and given him a name which is above every name: 10 That at the name of Jesus every knee should bow, of things in heaven, and things in earth, and things under the earth; 11 And that every tongue should confess that Jesus Christ is Lord, to the glory of God the Father.

Let us follow His example and fully experience the grace of God.