God's plan does not change with regard to Moses, but Moses changes to align with God's plan (Exo 3:7). God's plan is personal, historical (relates to a set time and event), geographic (the right place), operational (requires deeds, actions), motivational (God wants us to be motivated by love 2Co 5:14), inspirational (the Word of God is our inspirational power), and is unconventional (Isa 55, Psa 103). Our weakness (insufficiency) is the key to benefiting from God's strength, sufficiency (Exo 3:11, 2Co 12:9-10). Moses failures where do to trying to do the right thing at the wrong time and wrong way (Act 7:22-25, Exo 2:11-15). Moses' wounds from past failure come out in his conversation with God; he pleads inadequacy (Exo 3:11-12), and ignorance (Exo 3:13-14, Act 7:22). Moses expresses frustration and bitterness. God responds by telling of His vital role, and promise (Exo 3:14-22). Moses excuse of being rejected (Exo 4:1), makes God more abrupt; He gives Moses signs (Exo 4:2-9). Moses denies his skill (Act 7:22, 1Co 2:1-5, Exo 4:10), and refuses to go -- his bitterness (Exo 4:13). God's anger at Moses comes out (Exo 4:14). God forces Moses to speak through Aaron (divine sarcasm - as Aaron was not nearly as skilled - Exo 4:15-17). Moses does overcome, of course (Deu 33:1). This should be an encouragement to us.