If thou hast run with the footmen, and they have wearied thee, then how canst thou contend with horses? and if in the land of peace, wherein thou trustedst, they wearied thee, then how wilt thou do in the swelling of Jordan?
If thou hast run with the footmen, and they have wearied thee, then how canst thou contend with horses? - Yahweh's reply to Jeremiah's complaint - i:e., horsemen: the argument a fortiori. A proverbial phrase. The injuries done thee by the men of Anathoth ("the footmen") are small compared with those which the men of Jerusalem ("the horsemen") are about to inflict on thee. If the former weary thee out, how wilt thou contend with the king, the court, and the priests at Jerusalem?
(Wherein) thou trustedst, (they wearied thee). The English version thus fills up the sentence with the italicized words, to answer to the parallel clause in the first sentence of the verse. The parallelism is, however, sufficiently retained with a less ellipsis. 'If (it is only) in a land of peace thou art confident' (Maurer).
How wilt thou do in the swelling of Jordan? In harvest time and earlier (April and May) it overflows its banks (Joshua 3:15), and fills the valley called the Ghor. Or, 'the pride of Jordan'-namely, its wooded banks, abounding in lions and other wild beasts (Zechariah 11:3, "The pride" [nª'own-the same Hebrew word as here is translated the swelling] "of Jordan is spoiled;" cf. 2 Kings 6:2, implying its wooded character). Maundrell says that between the Sea of Tiberias and Lake Merom the banks are so wooded that the traveler cannot see the river at all without first passing through the woods. If in the champaign country (alone) thou art secure, how wilt thou do when thou fallest into the wooded haunts of wild beasts? (cf. Proverbs 24:10.)