The first quote I learned from Dead Poet's Society when I was a teenager. In college I cross-stitched it with a pretty border and hung it on my wall.
The second quote I just found this week.
The gospel of Jesus Christ is a divine and perfect plan. It is composed of eternal, unchanging principles and laws which are universally applicable to every individual regardless of time, place, or circumstance. The principles of the gospel never change.Elder Poelman goes on to talk about Leviticus, which teaches such principles as revelation and caring for the poor, but also lays out policies such as that an employer must pay each of his workers at the end of every day (which obviously is something that has changed with time). Then he continues:
The Church of Jesus Christ of Latter-day Saints is a divine institution administered by the priesthood of God. The Church has authority to teach correctly the principles and doctrines of the gospel and to administer its essential ordinances.
The gospel is the substance of the divine plan for personal, individual salvation and exaltation. The Church is the delivery system that provides the means and resources to implement this plan in each individual's life.
Procedures, programs and policies are developed within the Church to help us realize gospel blessings according to our individual capacity and circumstances. Under divine direction, these policies, programs, and procedures do change from time to time as necessary to fulfill gospel purposes. Underlying every aspect of Church administration and activity are the revealed eternal principles [of the gospel] as contained in the scriptures.
As individually and collectively we increase our knowledge, acceptance, and application of gospel principles, we become less dependent on Church programs [to tell us what to do]. Our lives become gospel centered.
Sometimes traditions, customs, social practices and personal preferences of individual Church members may, through repeated or common usage be misconstrued as Church procedures or policies. Occasionally, such traditions, customs and practices may even be regarded by some as eternal gospel principles. Under such circumstances those who do not conform to these cultural standards may mistakenly be regarded as unorthodox or even unworthy. In fact, the eternal principles of the gospel and the divinely inspired Church do accommodate a broad spectrum of individual uniqueness and cultural diversity.
It is important therefore to know the difference between eternal gospel principles which are unchanging [and] universally applicable, and cultural norms which may vary with time and circumstance.
The source of this perspective is found in the scriptures…[as the gospel] is taught by various messengers at different times and places. In the scriptures we discover that varying institutional forms, procedures, regulations and ceremonies are utilized, all divinely designed to implement eternal principles. The practices and procedures change; the principles do not.
Through scripture study we may learn eternal principles and how to distinguish them from and relate them to institutional resources. As we liken the scriptures unto ourselves we can better utilize the institutional resources of the modern restored Church to learn, live and share the gospel of Jesus Christ.
Every church member has not only the opportunity, right, and privilege to receive a personal witness regarding gospel principles and Church practices, but has the need and obligation to obtain such assurance by exercising his free agency, thereby fulfilling one purpose of his mortal probation.