Psalm ix. is imperfectly acrostic. It falls into strains of two verses each, which are marked by sequence of thought as well as by the acrostic arrangement. The first begins with Aleph, the second with Beth, and so on, the second verse of each pair not being counted in the scheme. The fourth letter is missing, and ver. 7, which should begin with it, begins with the sixth. But a textual correction, which is desirable on other grounds, makes the fifth letter (He) the initial of ver. 7, and then the regular sequence is kept up till ver. 19, which should begin with the soft K, but takes instead the guttural Q. What has become of the rest of the alphabet? Part of it is found in Psalm x., where the first verse begins with the L, which should follow the regular K for ver. 19. But there is no more trace of acrostic structure in x. till ver. 12, which resumes it with the Q which has already appeared out of place in ix. 19; and it goes on to the end of the alphabet, with only the irregularity that the R strain (x. 14) has but one verse. Verses with the missing letters would just about occupy the space of the non-acrostic verses in Psalm x., and the suggestion is obvious that the latter are part of some other psalm which has been substituted for the original; but there are links of connection between the non-acrostic and acrostic portions of Psalm x., which make that hypothesis difficult. The resemblances between the two psalms as they stand are close, and the dissimilarities not less obvious. The psalmist's enemies are different. In the former they are foreign, in the latter domestic. Psalm ix. rings with triumph; Psalm x. is in a minor key. The former celebrates a judgment as accomplished which the latter almost despairingly longs to see begun. On the whole, the two were most probably never formally one, but are a closely connected pair.