A person who is lukewarm in the Faith was hot at some point, and the only way to restore this spiritual gift is through repentance. This is why repentance is a gift from God! While there is repentance, there will be salvation; when there is no repentance, there is no longer salvation. In other words, a person may have committed the biggest mistakes, but if there is repentance, he will acknowledge them, confess, turn away and hate those sins.
This way, he will have the opportunity to return to his First Love, and, if he never had an encounter with his First Love, he will, because he will make a Covenant with God and keep this Covenant alive.
But, who should be zealous? Who should repent? The person!
And I ask: when is a person zealous and repents? When he is humble enough to acknowledge it. When a person is proud, he does not care about the things of the Spirit, on the contrary, he turns away from them, which is what happens with most people.
Most people pay attention to their physical needs – family, love life, job, finances, education, etc. – and disregard their spiritual life, which is their communion with God, because they are not humble enough to acknowledge this part.
Note that nowadays there is a great lack of respect for the Word of God. So how and when do we show respect for the Word of God? When we practice it! When I listen, read and understand, accept and practice. This is how I can show zeal for the Word of God. And do not forget that God and His Word are the same person. Therefore, when I disregard the Word of God, I am disregarding God Himself.
So, when someone wants to abandon sin, abandon his or her old life and live in godliness, in communion with God, it is fundamental that they observe the Word of God!