μέλλω,
[in LXX: Jb 3:8 (עָתִיד) 19:25 (אַחֲרוֹן); elsewhere for fut., and freq. in Wi, II, IV Mac;]
to be about to be or do;
1. c. inf. (Bl., § 62, 4; 68, 2; M, Pr., 114);
(a) of intending or being about to do of one's own free will: c. inf. praes., Mt 2:13, Lk 10:1, Ac 3:35:35, He 8:5, II Pe 1:12 (Field, Notes, 240), al.; c. inf. aor. (Bl., § 58, 3), Ac 12:6, Re 3:16;
(b) of compulsion, necessity or certainty: c. inf. praes., Mt 16:27, Lk 9:31, Jo 6:71, Ro 4:24, al.; c. inf. aor., Ro 8:18, Ga 3:23, Re 3:212:4.
2. Ptcp., ὁ μέλλων: absol., Ro 8:38, I Co 3:22; τὰ μ., Col 2:17; εἰς τὸ μ. (Field, Notes, 65); c. subst., Mt 3:712:32 (ὁ αἰὼν ὁ μ.; LXX for עַד), Ac 24:25, I Ti 4:8, He 2:5, al.