There shall nothing cast their young, nor be barren - Hence there must be a very great increase both of men and cattle.
The number of thy days I will fulfill - Ye shall all live to a good old age, and none die before his time. This is the blessing of the righteous, for wicked men live not out half their days; Psalm 55:23.

There shall nothing cast their young, nor be barren in the land,.... There shall be no abortions or miscarriages, nor sterility or barrenness, either among the Israelites, or their cattle of every kind, so that there should be a great increase, both of men and beasts:
the number of thy days I will fulfil; which was fixed for each of them, in his eternal purposes and decrees; or what, according to the temperament of their bodies and the course of nature, which, humanly speaking, it might be supposed they would arrive unto; or generally the common term of human life, which, in the days of Moses, was threescore years and ten, or fourscore, see Job 14:5, it may be considered whether any respect is had to the time of their continuance in the land of Canaan, the term of which was fixed in the divine mind, or the fulness of time in which the Messiah was to come.

The number of thy days I will fulfill - And they shall not be cut off in the midst by untimely deaths. Thus hath godliness the promise of the life that now is.