"Yet ye say, Wherefore? Because the LORD hath been witness between thee and the wife of thy youth, against whom thou hast dealt treacherously: yet is she thy companion, and the wife of thy covenant. And did not he make one? Yet had he the residue of the spirit. And wherefore one? That he might seek a godly seed. Therefore take heed to your spirit, and let none deal treacherously against the wife of his youth. For the LORD, the God of Israel, saith that he hateth putting away: for one covereth violence with his garment, saith the LORD of hosts: therefore take heed to your spirit, that ye deal not treacherously."
Certainly He made them to "be fruitful, and multiply!" Because "This is a great mystery: but I speak concerning Christ and the church!" The very covenant of matrimony is a parable or analogy of our covenant to God in Christ Jesus.
As to whether the barren should marry, were Abram and Sara in transgression (who begat Ishmael and Isaac)? Isaac and Rebekah (and begat Esau and Jacob)? Manoah and his wife (who begat Samson)? Elkanah and Hannah (who begat Samuel)?
"Sing, O barren, thou that didst not bear; break forth into singing, and cry aloud, thou that didst not travail with child: for more are the children of the desolate than the children of the married wife, saith the LORD. Enlarge the place of thy tent, and let them stretch forth the curtains of thine habitations: spare not, lengthen thy cords, and strengthen thy stakes; For thou shalt break forth on the right hand and on the left; and thy seed shall inherit the Gentiles, and make the desolate cities to be inhabited. Fear not; for thou shalt not be ashamed: neither be thou confounded; for thou shalt not be put to shame: for thou shalt forget the shame of thy youth, and shalt not remember the reproach of thy widowhood any more. For thy Maker is thine husband; the LORD of hosts is his name; and thy Redeemer the Holy One of Israel; The God of the whole earth shall he be called. For the LORD hath called thee as a woman forsaken and grieved in spirit, and a wife of youth, when thou wast refused, saith thy God. For a small moment have I forsaken thee; but with great mercies will I gather thee. In a little wrath I hid my face from thee for a moment; but with everlasting kindness will I have mercy on thee, saith the LORD thy Redeemer."
For the PROMISE of the LORD to "be fruitful," if not fulfilled in the flesh, must be fulfilled in the Spirit (that there be no schism in the body)! Wherein as many dispute that all the covenants of God are applicable to believers, the covenant of Abraham does apply, according to the promise and example of God, you must bear fruit, even as God in whose likeness and image you were made has shown. Wherein each of these children, along with the miraculous conception of Christ Himself represent the faithfulness of God in fulfilling His Word (who ordained marraige after the similitude of Christ and the Church)!