The tension is built by the use of certain pitches which move us away from the point of rest. This is a wonderful example of a simple melody which follows the sabbath principle and, as a result, is a great melody. The element of rhythm is also used to create tension and rest in a variety of ways. One important way is the use of syncopation. In order to understand syncopation, beat and meter must be understood.
Meter is a regularly recurring accent within the pulse.
Beats two and four are unaccented. Syncopation takes place when an accent is misplaced, i.e., placed on an unaccented beat. Syncopation in effect contradicts the prevailing meter and as such creates tension. In the hands of a good composer it is a rhythmic device that can be used to propel the movement of the music in useful and beautiful ways. The Genevan Psalms are full of syncopations, which is why they were often called Genevan jigs.