My friend told me that regular people like him/her who work, maintaining the precepts is enough no need to meditate. How can I explain to him/her?

You must look at the state of his/her mind.  Where is he/she mentally?  In giving an answer so a person sees the importance of meditation, look at this first. Look at how he/she is normally. How interested is he/she in the teachings of the Lord Buddha?  Some people are not at all interested in the Lord Buddha’s teachings.  But they make offerings to monks during alms rounds, give to charity, and maintain the precepts.  They do this as a tradition.  This is one group.

The second group of people is determined to make offerings to monks, diligently maintain the precepts, and learn about Dhamma also.  They study the ways in which they can maintain the precepts very well.  What are the rules?  How can they make offerings to gain the greatest merit?  But they do not see the value of meditation. In fact, some of them learn meditation but some teachers, some of whom are monks, would say that they do not meditate, they already have concentration, they are doing well already. Why do they have to meditate?  Oh, there is this as well.

So by this, you must see for yourself what is your friend’s group.  Point this out to him also.

One group makes offerings to monks and maintains the precepts according to tradition.  They follow the traditions.  In this case, you must suggest that their offerings make them feel content.  Then you must further suggest that if they want to increase their merit before making an offering, they should try meditating before.  This will make their minds clear.  The merit they earn will be of higher quality than the merit from simply making an offering. 

Or they are maintaining the precepts; this is good.  It is the same situation.  Maintain the precepts well and meditate also.  This will be great because the mind will be clear.  The meditation will be more stable.  All these things can be explained at this level.  Do it gradually.

But after they have meditated for some time, explain things to them at a deeper level.  It depends on what you consider appropriate for them. Use your experiences from your years of meditation to gradually explain to them.  They will easily understand by themselves.

As for those who have diligently studied Dhamma, those who study how to make offerings, how to maintain the precepts, those who enjoy reading Dhamma but do not like meditation. Because they think it is unimportant.

As for this group that does not see the importance of meditation, if these people are not against meditation, it is possible to explain meditation to them at one level.

For example, even if we make an offering to eliminate our stinginess, our attachment to our possessions, it is good to make such an offering. 

Diligently maintaining the precepts makes us determined to control our manners, suppresses our passions physically, verbally, and mentally.  So this is good, to maintain the precepts well.  But your minds are not yet clear enough.  When your mind is not clear enough, your must think in the following way.  Here is an example.  Now you are diligently making offerings and maintaining the precepts regularly.  But there are many times when you are hit with things that make you gloomy, that prevent you from sleeping, that create mental commotion.  Sometimes these things make you have conflicts that cause divisions with your friends.  Don’t you want to solve these problems?

The method for solving these problems that does not require a big investment is to meditate. Meditation is training to control the mind.  For people like this, urge them to meditate as a way to control their minds.

For another group, they are the hard workers.  If you invite them to meditate, even if they do not have conflicts with anyone, yet they work hard and reach a point where they are tired.  The way to cure them of their weariness, nothing is better than meditation.  Meditation will eliminate their fatigue, their weariness, their boredom.  It is a way to support them mentally.  It revitalizes their minds, clears their minds, fosters self-support.

To put this more simply, seek out the various beneficial aspects of meditation that can be used to explain to them.  Make the explanation fit their conduct and behavior.  When you find something that is appropriate, use it.  Then you can invite them to come to the temple to meditate with you.  This is not too difficult to handle.

I would like to add one more thing. The times that when people can be invited most easily, even when they are normally quite stubborn, are: when the person is sick when the person is suffering due to their family, their job, or whatever source of suffering.  When they are suffering, they look for support.

When they are sick, they are in physical torment.  They want support.Whether it is physical or mental suffering, they want support.  This is the moment to invite them to meditate.  You will not leave anyone behind.