John 14:21

He that hath my commandments, and keepeth them
He that has not merely the external revelation of them in the Bible; but has them written on his heart, by the finger of the Spirit of God, and keeps them under the influence of grace and strength received from him:

he it is that loveth me:
others may talk of loving Christ, but this is the man that truly does love him; for his observance of Christ's commands is a proof and evidence that he loves him not in word only, but in deed and in truth: and to encourage souls to love and obedience, Christ adds,

he that loveth me, shall be loved of my Father;
not that love to is the cause, condition, or motive of the Father's love to his people; nor does his love to them begin when they begin to love Christ; but this expression denotes some further and greater manifestation of the Father's love to such persons, and shows how grateful to the Father are love and obedience to the Son:

and I will love him;
which must be understood in the same manner; Christ does not begin to love his people when they begin to love, and obey him; their love and obedience to him, spring from his love to them; which love of his towards them was from everlasting: but this phrase signs a clearer discovery of his love to them, which passeth knowledge; and some fresh mark and token of his affection for them; and which is explained in the next clause:

and will manifest myself to him;
not in a visible way, or in a corporeal form, as he did to his disciples after his resurrection; but in a spiritual manner, as when he makes himself known to his people in ordinances, and favours them with communion with him, and they see his beauty, his fulness, his grace and righteousness, his power, and his glory.