Deuteronomy 30:20

20 to love Jehovah thy God, to hearken to His voice, and to cleave to Him (for He [is] thy life, and the length of thy days), to dwell on the ground which Jehovah hath sworn to thy fathers, to Abraham, to Isaac, and to Jacob, to give to them.'

Deuteronomy 30:20 Meaning and Commentary

Deuteronomy 30:20

That thou mayest love the Lord thy God
And show it by keeping his commands:

[and] that thou mayest obey his voice;
in his word, and by his prophets:

and that thou mayest cleave unto him;
and to his worship, and not follow after and serve other gods:

for he [is] thy life, and the length of thy days;
the God of their lives, and the Father of their mercies; the giver of long life, and all the blessings of it; and which he had promised to those that were obedient, to him, and which they might expect:

that thou mayest dwell in the land which the Lord sware unto thy
fathers, to Abraham, to Isaac, and to Jacob, to give them;
the land of Canaan, often thus described; this was the grand promise made to obedience to the law, and was typical of eternal life and happiness; which is had, not through man's obedience to the law, but through the obedience and righteousness of Christ.

Deuteronomy 30:20 In-Context

18 I have declared to you this day, that ye do certainly perish, ye do not prolong days on the ground which thou art passing over the Jordan to go in thither to possess it.
19 `I have caused to testify against you to-day the heavens and the earth; life and death I have set before thee, the blessing and the reviling; and thou hast fixed on life, so that thou dost live, thou and thy seed,
20 to love Jehovah thy God, to hearken to His voice, and to cleave to Him (for He [is] thy life, and the length of thy days), to dwell on the ground which Jehovah hath sworn to thy fathers, to Abraham, to Isaac, and to Jacob, to give to them.'
Young's Literal Translation is in the public domain.