The Hebrew verb root sharat describes serving by attending, waiting on, or tending to a person or to assigned duties. For example, the daily actions by which Joseph served Potiphar and the chief jailer are called "attendance" in Genesis 39:4 and 40:4, even though Joseph's job description was "slave" instead of "attendant" (unlike Joshua in Exodus 24:13).
Biblical Hebrew will also sometimes use various phrases to replace sharat, such as an attednant "coming before" or "standing before" the person being served.
The Greek word diakoneo is the equivalent Greek word. It is the verb form of diakonos ("attendant, waiter at tables") and means "to wait upon, attend, or tend to". These words, often translated "minister" or "ministry", relate to the office of congregational helper mentioned in the third chapter of First Timothy.
The tribe of Levi waits on the Aharonic priesthood (Numbers 3:6), just as the Aharonic priesthood waits on God (many verses!). When used to refer to Tabernacle service, sharat appears to describe an attitude and state of readiness, in constrast to avodah which describes the actual labor done by the priests.
Yeshua said he did not come "to be waited upon, but to wait on by giving his life as a ransom for many" (Matthew 20:28 and Mark 10:45). Indeed, we read of few accounts of people waiting on Yeshua (parenthetically, nearly all such attending is done by women: Matthew 27:55, Mark 15:41, and Luke 8:3). Yeshua's followers should wait on the needy, for in his empathy Yeshua sees this as waiting on him (Matthew 25:44) and we will be rewarded (Hebrews 6:10).
Angels are like "public servants" of God who nevertheless "wait on" to God's people (Hebrews 1:14).
In the World to Come, Yeshua himself will wait on us (Luke 12:37), but we must have the attitude of being willing to wait on him (Luke 17:8-10).
Yeshua's words to Martha are well-known: do not be too busy waiting on people when you could be at Yeshua's feet (Luke 10:40-42).
We should wait on Yeshua by following him (John 12:26). The specifics of how to do this will be told to us by Yeshua (Acts 20:24). Thus we will have jobs we can call "our service" (Acts 21:19 and Romans 11:13) which we can "fulfill" (Colossians 4:17).
Waiting on Adonai makes use of spiritual gifts (Romans 12:7 and First Corinthians 12:4-5) as well as a general "great commission" of bringing reconciliation between God and the world (Second Corinthians 5:18).
This verb is the one used primarily in Matthew 20:25-28 (and the paraphrase in Luke 22:26-27). Yet even though "the leaders must become those who wait on you" it was not proper for the apostles to attend to the distribution of food rather than the Word of God and prayer (Acts 6:2-4).
Revelation 2:19 mentions a sequence of virtue: works, then selfless love, then waiting on, then conviction, then patience, then greater works.
Metaphorically, people "wait on Adonai" as a witness of God's power and ways. This can happen through how condemnation or death affects people as well as through how God's Spirit and glory affects people (Second Corinthians 3:7-9).
So how do we serve each other in a diakoneo manner?
We are given things to give each other. Spiritual gifts, especially, are given in order to attend to each other. We should not be hesitant to give out what God gives us, or to ask when we have need: this is part of being one body.
Besides spirtual gifts we can share hospitality. There are many scriptural precedents for attending on people by providing room and board!
Sometimes a "listening ear" is a great thing to give someone.
Mentoring and/or being a prayer and accountibility partner with someone also fit this type of serving.
We can pass along stuff we no longer need (i.e., children's clothes) or loan out stuff helpfully (i.e., use of a truck or computer scanner). Needs of this sort can be anonymously shared when appropriate.
This diakoneo manner of serving, unlike the others ("bondlsave" and "laboring"), can be assigned contractually. Some ways the community edifies and equips itself benefit from specialization. Both First Corinthians 9:4-13 and First Timothy 5:17 are normally understood as teaching that a congregation may assign someone to specialize in teaching, music, dance, and so forth, and that such people may be paid for their work. A congregation is supposed to provide for all its members; how much more is it responsible for people who devote much time to supporting it!
We can attend to each other financially with monetary charity (Acts 11:29, 12:25; Romans 15:25,31; also much of Second Corinthians 8-9). One useful and scripturally-based system is an interest-free loan fund for members, to help people jointly be prepared for unexpected expenses just as we would care for ourselves. Another system is using home tzedakah boxes for anonymous needs of poor congregants (letting someone in leadership administer the money confidentially). Both saving to deal with unexpected expenses and spending money on needs are ways we care for ourselves which we can extend as part of loving our neighbors as ourselves.
Most Americans are much more comfortable, especially in a religious setting, with the first two kinds of attending. There is a typical American reaction to both being a servant and being held to standards. Most Americans enjoy being a helper, and enjoy setting goals, but the combination of serving others and having standards makes many Americans bristle. What began historically as a "pioneer spirit" of independence has become a focus on individual performance and competitiveness in public schools, educational testing, and many low-income jobs.
Unfortunately, this means many Americans never learn how to be good servants. If education neglects teaching how to be a team player and how to serve a boss, or even worse confuses any valid service with "brown nosing" or trying to become the "teacher's pet", then people develop personalities only suitable for low-income jobs and family strife. Most jobs that are part of a career path are in a setting that values appropriate and good service. Many people wonder why their boss does not promote them even while their behavior reamins stuck in the school mindset of trying to be "ahead of the curve" rather than a team player; people who succeed in a career path are usually much like Yosef.
The "pioneer spirit" does encourage creativity, ingenuity, fortitude, and risk-taking. But it needs to be balanced with a spirit desiring to be a good servant to Adonai as well as to family members and other people.
A congregation develops a sense of family-like community to promote teamwork and disarm the "pioneer spirit". Yet even in healthy congregations very few people come to their congregational leader and ask, "What can I do to fulfill the vision God has given the leadership of this congregation?" Most people come with their own ideas or agendas, wanting to fit those into the congregation. (It can also be true that congregational leadership fails in its responsibility to define the congregation's vision, to communicate it clearly and frequently, and to structure the congregation to fulfill it. The leadership should be "trustees" of God's truth and wisdom (First Corinthians 4:1) and thus of the power these provide (First Corinthians 1:18, 2:4).)
Moreover, few people have experience in serving their peers in all three aspects of bondslave, laboring, and waiting on. Many people are not receptive to being told not only that they need to serve their peers "more" or "better", but even in a totally new way.
Yet if every believer was proficient at serving there would be no stopping the advance of the Kingdom of God! We need to remember that Adonai enables us to serve well, and to serve in every way we should be serving, to all the people we should be serving.