What does John 14:24 mean?

Scripture does not teach that "good behavior" earns or keeps salvation (Titus 3:5; Romans 11:6). There is no valid scriptural argument that people must act in certain ways to merit a ticket to heaven (Isaiah 64:6; Galatians 2:21). The Bible also rejects the idea that Christians can expect to be perfectly sinless (1 John 1:9–10). We will fail, at times (James 3:2). However, Scripture is also clear that those who are saved through faith in Christ will demonstrate that salvation in their lives (John 14:15, :21, 23). Claims that someone is a true "Christian" are incompatible with a life lived in defiance of His teachings (1 John 2:4–6). Works are not required for salvation, but true salvation produces corresponding works (James 2:14–18).

This verse reiterates that same idea. Jesus is God (John 14:9). To reject Jesus is to reject God (John 5:30; 12:49). Those who reject God are rejecting the Holy Spirit (John 14:16–17), and that means they'll disobey the commands taught by Jesus. This is a sign of their lack of faith (John 8:39–40, 8:44).