Many different views on practices in Christian ethics could be explored: one should be aware of different ways to think about practices. This brief essay begins with one particular way of thinking about practices that is significant in the United States, since it undergirds much of American philosophy on education: pragmatism. The essay then offers brief introductions to a series of other views on practices.
An emphasis on 'practice' in enquiry in Western philosophy comes from the anti-idealist philosophers at the end of the 19th and into the 20th century. This includes British (e.g., G. E. Moore, Bertrand Russell) and American realism, but here I will note only American pragmatism, with its emphasis on actions and practices.
The pragmatist movement formed an essential part of American philosophy. It was particularly associated with the names of Charles Peirce (who used the term 'pragmaticism'), William James (who thought of this movement as a 'radical empiricism'), and John Dewey (who also linked his thought with empiricism, calling it 'empirical naturalism'). Pragmatism was a response to idealism and the rationalism it represented in the 19th century. Frederick Copleston describes William James' view as follows:
The rationalist philosopher, as James sees him, moves from the whole to its parts, from the universal to the particular, and he endeavours to deduce facts from principles. Further, he tends to claim final truth on behalf of his system of deduced conclusions. The empiricist, however, starts with particular facts; he moves from parts to wholes; and he prefers, if he can, to explain principles as inductions from the facts. Further, the claim to final truth is foreign to his mind.
Moreover, the validity of a view is, for the pragmatist, found in its successful function. This also means, as Ferdinand Schiller (1864-1937) pointed out, that abstract ideas are not valid, since they must be seen in conjunction with concrete contexts. This is precisely the reason why 'absolute truth' is seen to be impossible and unpragmatic. Schiller opposed the idealist notion that the Absolute was the central concept in philosophy and instead located humans in its place.
Dewey's 'empirical naturalism' understands thought in a natural and pragmatic way: thought is a product of experiences and leads to action and further experiences (it is 'empiricist' and pragmatic); and it is a 'response' to 'stimuli' in the environment (natural and cultural) and it seeks to bring about change in that environment (it is part of a 'natural,' evolutionary process). Knowledge, on this account, is not understood as mere observation of an object, where the spectator and the object are independent. Rather, knowledge entails a forming of the object (which exists independent of the knower, contra Bergson, but is not known in itself, contra the idealists). Simply put, we 'know' things in terms relevant to us; we see them in terms of their function or usefulness in our environment. And this means that theory cannot be divorced from practice.
Dewey is thus reacting to a rationalist, scientific account of the world that is dualistic, that separates the mechanical world to be 'observed' by scientists from the world of values. He is also reacting to an abstract approach to thought and instead wants to focus on experience and concrete situations. Dewey does not denigrate 'theory'; he only insists that theory must not be separated from experience. He understands, for example, 'truth' as instrumental--truth is what works in addressing a problematic situation. Morality too has a natural and instrumental definition: we are formed by our habits (or customs) and dispositions, which are initially informed by our instincts or impulses, and the former give rise to our moral vision (to use a more contemporary term). Values are not eternal or independent from facts. As opposed to 'truth' or 'morality' in any static sense, instrumentalism prefers to speak of intelligence that grasps and effects new possibilities of growth, of the 'continuous reconstruction of experience' (Dewey, A Pluralistic Universe, p. 311). Education, for example, is not a preparation for life but a process of living (Dewey, Formal Logic, p. 382), a process that is an end in itself. It should not be about the study of 'subjects' but about social formation that will make of students good citizens who will contribute to the ongoing growth of society. Remaining consistent to his pragmatic philosophy, Dewey defines his notion of growth in various areas not in terms of 'ends' but in terms of 'means,' what functions best given the problem faced in the present situation. Thus Dewey states for philosophy--politics, ethics, education in particular--what Charles Darwin did for biology: growth is a result of responding well to stimuli in the environment that require change.
Philosophical pragmatism holds to a different understanding of ‘truth’ from any notion of absolute truth—i.e., that truth is absolute, unchanging, and eternal. It is different from a correspondence theory of truth, which says that what a knower knows in his or her symbolic representation of reality in words, pictures, and ideas corresponds to what is objectively out there. An emphasis on pragmatism leads Peirce, James, and Dewey to describe ‘truth’ in the following ways: 
Charles Peirce: truth is understood as the consensus of those investigating the matter.
William James: truth is what satisfies (combining a human element with a pragmatic
Instrumentalist view: truth is what works in transforming a problematic situation (Dewey, The Meaning of Truth, p. 154).