An unbeliever can’t obey God. It is impossible for them to do and most have no desire at all to obey or please God. The natural man wants to glorify himself and not glorify the one who made all things and sustains all things.
By this we know that we love the children of God, when we love God and obey his commandments. For this is the love of God, that we keep his commandments. And his commandments are not burdensome. 1 John 5:2-3 ESV
This isn’t true for the believer because we have faith to please Him.
When we obey God, it proves our love for Him, it glorifies Him to the world, it shows the world our loyalty to Him, and it opens avenues for blessings for us. Here’s the thing, we obey His commandments, not because we have to, but because we desire to, because we love Christ. We are not walking in the flesh any longer. We are walking by the spirit and we are a new creation.
However, when we disobey God it is an act of rebellion, it is sinful, it is a form of idolatry, it disrespects God’s word, and at times is based on looking good to other people rather than the Lord.
If we love the Lord, we will have a desire to obey him, not always perfectly, but our desire to obey Him and our lives give evidence of that desire. It assures us that we belong to Him. God commands us to obey Him throughout the pages of scripture. And when we do it brings us joy, confidence, peace, comfort, and blessing in a world where people are searching for these things in everything other than Christ.
It doesn’t matter how much knowledge we have if we refuse to obey the Lord. Obey not out of obligation or duty but obey because you love Christ.
“If I could simplify the Christian life to one thing, it would be obedience.” John MacArthur