أُجِيبُ دَعْوَةَ الدَّاعِ إِذَا دَعَانِ
I respond to the call of the caller when he calls upon Me.
In 2:186 the assertion of nearness is immediately followed by the promise to respond to a supplicant. Idhā daʿān specifies the situation of calling upon God. The juxtaposition creates a visible thematic bond between nearness and answered prayer.
Rhetorical analysis of this clause cannot by itself settle every theological or legal question about the manner or timing of response. Those questions need their own evidence; the local rhetorical point is reassurance and relational immediacy.