1812. 'He believed in Jehovah' means the Lord's faith at that time. This is clear from the words themselves, and also from the train of thought in the internal sense, the train of thought being that while He lived in the world the Lord was engaged repeatedly in conflicts brought about by temptations, and was repeatedly victorious. And what is meant here by 'believing in Jehovah' is the truth that the Lord was filled repeatedly with an inmost confidence and faith that, because it was pure love out of which He was fighting for the salvation of the whole human race, He could not but be victorious. From the love out of which anyone fights it is known what his faith is. A person who fights out of any other love than love towards the neighbour and love towards the Lord's kingdom is not fighting out of faith, that is, he does not believe in Jehovah but in that which he loves; for the love itself for which he fights constitutes his faith. Take, for example, one who fights out of the love of becoming the greatest in heaven. He does not believe in Jehovah, but rather in himself, for wishing to become the greatest is wishing to have control over others. Thus he fights for control. It is the same with every other example that may be taken. From the love itself therefore out of which a person fights one may know what his faith is.
 The Lord however, in all His conflicts brought about by temptations, never fought out of self-love, that is, for Himself, but for all throughout the universe. He did not fight therefore to become the greatest in heaven, for that is contrary to Divine love. He scarcely did so to become the least. He fought solely so that all others might become something and be saved, as He Himself also declares in Mark,
The two sons of Zebedee said, Grant us to sit in Your glory, one on Your right hand and the other on Your left. Jesus said, Whoever would be great among you must be your minister, and whoever would be first among you must be slave of all. For the Son of Man also came not to be ministered to but to minister, and to give His life 1 as the price of redemption for many. Mark 10:37, 43-45.
This is the love, that is, the faith, out of which the Lord fought, and which is meant by 'believing in Jehovah'.
1. literally, soul
(References: Mark 10:35)