The passage basically talks about two things:

The priest who presented the offering must be clean before he may be in contact with the sacred things of God.

The sacrifice items must be without blemish.

Observes the order. The priest must be right before ensuring the offering is perfect! Next, observes the things that make a priest unclean: infectious skin, touching unclean things and emission of semen. Some of these things are natural, and others are beyond their control. In other words, the priest must be actively preserving himself clean. He cannot say that he touches the unclean things unintentionally and thus get away with it. That is the attitude God expected from us, as all believers are priests of God. We must always ensure ourselves right before God before asking if our service is acceptable. To be right before God, we must actively abstain from all wrongdoing. It has to be a conscientious effort.

Next, ensure our sacrifice or our service is without blemish. In short, we must put in our best effort every time we serve. I remember the demand of my lecturer telling us that writing a sermon script should take only 30% of our preparation time. The remaining 70% is for editing and practising. I think that has to be applied to everything we do, presenting a song, leading a service, teaching a Sunday School, or even telling a story to children. No one is naturally good at what they do. Often, those who are good put in a remarkable amount of practice time to ensure perfection.

I was very impressed with one of my church pianists for playing the prelude before the start of service. She managed to end precisely when the counter turned zero. After the worship, I went over to thank her. She told me that she had been practising to get that right. Yes, this is the attitude we need in presenting our offering to God.

May God help us always serve Him with the right attitude. May God bless all of you!