malachi 4:2 But unto you that fear my name shall the Sun of righteousness arise with healing in his wings; and ye shall go forth, and grow up as calves of the stall. - Free Bible Online

      2. The effect of the judgment on the righteous, as contrasted with its effect on the wicked (Mal 4:1). To the wicked it shall be as an oven that consumes the stubble (Mt 6:30); to the righteous it shall be the advent of the gladdening Sun, not of condemnation, but "of righteousness"; not destroying, but "healing" (Jer 23:6).
      you that fear my name--The same as those in Mal 3:16, who confessed God amidst abounding blasphemy (Isa 66:5; Mt 10:32). The spiritual blessings brought by Him are summed up in the two, "righteousness" (1Co 1:30) and spiritual "healing" (Ps 103:3; Isa 57:19). Those who walk in the dark now may take comfort in the certainty that they shall walk hereafter in eternal light (Isa 50:10).
      in his wings--implying the winged swiftness with which He shall appear (compare "suddenly," Mal 3:1) for the relief of His people. The beams of the Sun are His "wings." Compare "wings of the morning," Ps 139:9. The "Sun" gladdening the righteous is suggested by the previous "day" of terror consuming the wicked. Compare as to Christ, 2Sa 23:4; Ps 84:11; Lu 1:78; Joh 1:9; 8:12; Eph 5:14; and in His second coming, 2Pe 1:19. The Church is the moon reflecting His light (Re 12:1). The righteous shall by His righteousness "shine as the Sun in the kingdom of the Father" (Mt 13:43).
      ye shall go forth--from the straits in which you were, as it were, held captive. An earnest of this was given in the escape of the Christians to Pella before the destruction of Jerusalem.
      grow up--rather, "leap" as frisking calves [CALVIN]; literally, "spread," "take a wide range."
      as calves of the stall--which when set free from the stall disport with joy (Ac 8:8; 13:52; 20:24; Ro 14:17; Ga 5:22; Php 1:4; 1Pe 1:8). Especially the godly shall rejoice at their final deliverance at Christ's second coming (Isa 61:10).

JFB.