εἷς θεὸς καὶ πατὴρ πάντων, ὁ ἐπὶ πάντων καὶ διὰ πάντων καὶ ἐν πᾶσιν.
πᾶς is not used absolutely or in an unqualified sense here: it is utilized relatively. The apostle has the Christian congregation in mind, for it is this ecclesia that the one God and Father of all (εἷς θεὸς καὶ πατὴρ πάντων) especially rules "over" (ἐπὶ πάντων), works "through" (διὰ πάντων), and is "in" (ἐν πᾶσιν) by means of his holy spirit (2 Corinthians 6:14-18; Ephesians 2:19-22). Nevertheless, Paul is not espousing pantheism or panentheism in this account--his inspired counsel for the Ephesians strictly applies to the first-century Christian assembly composed of anointed ones, not to the cosmos as a whole.
William Larkin (Ephesians: A Handbook on the Greek Text, page 71):
εἷς θεὸς καὶ πατὴρ. Nominative subject of an implied equative verb. The combination of titles occurs consistently in Ephesians in formal or liturgical contexts: salutation, 1:2; doxology, 1:3; prayer, 1:17; thanksgiving, 5:20; benediction, 6:23 (cf. 3:9, 14).πάντων. Genitive of subordination. The fourfold πᾶς in this climactic statement probably all have the same gender, whether neuter or masculine (Best, 371). There is not enough in the context to distinguish the use of different genders with different items. Paul’s frequent cosmic focus in Ephesians, particularly with the use of πᾶς (1:10, 22, 23; 3:9, 15; 4:10), would be congruent with neuter gender. The term πατὴρ, however, denotes personal relationship, and the theme of church unity here (4:4) followed by a focus on individual church members (4:7) suggests that the gender is masculine and thus personal (contra Lincoln, 240; Best, 371).
