A drama aptly lit

Rembrandt's is not a harsh or hard light. The human beings he paints are not exposedm - nor are they flattered - by light; they are gentled by it. A softly achieved balance of illumination and shadows holds them in the realm of possibility rather than stark certainty, is tenderly suggestive rather than relentlessly factual.

Marvellously, this seventeenth-century Dutch artist's deeply sensitive painting of light is in tune with the manifest attitude of his maturity towards those moments of human drama - often biblical - he represents. This is never truer than in ''Jacob Blessing Ephraim and Manasseh.''

The expressiveness of hand and face, of attitude and posture, which are the language of narrative painting are certainly restrained if not downright enigmatic in such an example of Rembrandt's most fulfilled work. In contrast to the pictures of his youth, here is a happening of profound significance reduced to a human intimacy which powerfully engages the sympathy of the viewer, rather than simply his reaction. Meaning has become inherent rather than extrovert - something to be searched for in the mystery of experience and occurrence, as is often the case in everyday living. The indefinable is recognized as such. It is not changed into blatant theater.

''Jacob Blessing Ephraim and Manasseh'' is especially interesting in this respect because the treatment by artists of the subject had often in the past been highly dramatic. Pontormo and Guercino had both painted versions of the subject, which, as described in Genesis, involved an instant of disagreement between Jacob - the old patriarch nearing the end of his days - and his son Joseph (shown by Rembrandt wearing a turban), who has brought his sons to be blessed: a profoundly significant event.

Guercino in particular had rendered the story as an intense Baroque affair of momentous conflict, a clash of brilliant light and strong shadow, the figures all in movement, energized by a surge of feeling and will - his way of expressing the part of the Bible narrative where Joseph is ''displeased'' because his father deliberately gave his first blessing to Ephraim instead of Manasseh. The two children were Jacob's by his Egyptian wife Asenath, and they were on either side of the patriarch's bed. He crossed his arms so as to place his right hand on the head of the younger son, Ephraim. Joseph tried to interfere and, taking hold of his father's hand to move it to Manasseh's head, said:

''Not so, my father: for this is the firstborn; put thy right hand upon his head. And his father refused, and said, I know it, my son, I know it: he also shall become a people, and he also shall be great: but truly his younger brother shall be greater than he, and his seed shall become a multitude of nations.''

Guercino painted the disagreement. Earlier renderings of the subject had either presented the story as a simple and rather neutral Old Testament blessing of two boys by their grandfather, or, in line with a tradition that developed among early Christians, as a foretelling of the New Covenant. ''Ephraim,'' in this reading of the text, came to symbolize Christianity, while Manasseh symbolized the Jewish faith. Some of the earliest depictions of the subject emphasize this symbolism, which was reinforced by the crossing of Jacob's arms, taken to prophesy Jesus' cross.

Rembrandt's version of the subject is quite different from anything previous to it. For a start, he transfers the crossed hands from Jacob to the young boy, Ephraim, and further emphasizes the distinction bestowed upon him by hinting an aura round his head and a patch of light falling on his hands. In this Rembrandt quietly acknowledges the Christian tradition attached to the story.

At the same time, however - as pointed out by Wolfgang Stechow in a comprehensive article on the whole subject written in 1943 - Rembrandt ''achieved a profound synthesis of ideas springing from both the Old and the New Creed.'' The understanding shown by the artist towards Jewish people is well known, and he manages in this painting to override the conflict emphasized by other artists, with a feeling of universalm blessing. Although Jacob, as the Bible states, went against expectation and blessed the younger boy first, it is also true that the words he used in blessing both the lads stress the impartial grace of God. The beauty of this in a specific sense is that it was Jacob, as a young man, who had cheated his own elder brother out of his birthright and blessing. But now, by the time of his old age, he had grown to realize the sufficiency of God's blessing. It is this which Rembrandt seems to have visualized as the crux of his subject, and he presents a movingly peaceful and happy family ceremony with only the slightest hint that Joseph might be puzzled by his father's unorthodox action.

Rembrandt's originality of interpretation doubtless stemmed from his own thought and sensibility, together with his conviction that a loving God was as forgiving and universal as light.

But Wolfgang Stechow also points to a Jewish legend which certainly must have lent support to this depiction of the story, allowing the artist to avoid the emphasis on conflict shown in earlier pictures. According to the Pesikta Rabathim , Joseph had to persuade a reluctant Jacob to bless his sons at all, and it was only when he brought his wife Asenath before his father, saying, ''I pray thee, O father, do it for the sake of this righteous woman,'' that Jacob assented. This would explain the importance in Rembrandt's composition of the beautiful woman, standing at the side with such a touching and respectful presence - though according to the Bible narrative she wasn't there at all.