What does it mean to be rebellious? Isaiah 30:1 refers to the rebellious as being those who are uncontrolled (BB), self-willed (Moffatt), and make plans which are not devised by the Lord (NEB). Romans 10:21 further describes the rebellious as being disobedient (AAT), defiant (REB), or unruly (NEB). The rebellious argue with the Lord (NLT), contradict Him (Rotherham), oppose His plans (YLT) because they prefer their own will (Weymouth), and are stubborn (CEV). According to Isa 53:6 (cf. Rom 5:12), every human being is guilty of rebellion because we each want to be god of our own life, independently pursuing the path we want. God views rebellion as being like the evil of witchcraft (1 Sam 15:23, NJB).
One consequence of rebellion is that we hurt ourselves by falling away from God’s will (Hos 14:9, CW). Rebellion can be as simple as largely ignoring God and living a reasonably ‘good’ life as we see fit. This is rebellion where we drift from the Lord (Heb 2:1). As a result, the Lord has to discipline/punish us to try to get us back on track (Isa 1:5, NRSV). The rebellious path is a path of woe (Isa 30:1) because it results in God rejecting us (1 Sam 15:23) unless we truly repent from it.
We arrogantly think we know what would be better. Hence, we argue with Him, contradict Him, and go our own way. How can anything good come from opposing His plans? As C. S. Lewis put it, “O universal strength, I know it well. It is but froth of folly to rebel. For thou art Lord and hast the keys of Hell.” See Isa 66:24.
Instead of being timid, learn to be appropriately bold.