Tiberius, elated and overjoyed by his success, was all eagerness to bring on a decisive battle as soon as possible. He was, it is true, at liberty to act as he thought best owing to the illness of Scipio, but wishing to have his colleague's opinion he spoke to him on the subject. Scipio's view of the situation was just the opposite. He considered that their legions would be all the better for a winter's drilling, and that the notoriously fickle Celts would not remain loyal to the Carthaginians if the latter were kept in forced inaction, but would throw them over in their turn. Besides he hoped himself when his wound was healed to be of some real service in their joint action. On all these grounds therefore he advised Tiberius to let matters remain where they were. Tiberius was quite conscious of the truth and cogency of all these reasons, but, urged on by his ambition and with an unreasonable confidence in his fortune, he was eager to deliver the decisive blow himself and did not wish Publius to be able to be present at the battle, or that the Consuls designate should enter upon office before all was over — it being now nearly the time for this. Since, then, he did not choose the time indicated by circumstances, but his own time, his action was bound to be mistaken.
Hannibal's view of the situation was very much the same as Scipio's; so that he on the other hand was anxious to force a battle on the enemy, wishing in the first place to avail himself of the enthusiasm of the Celts while still fresh, secondly to encounter the Roman legions while still newly-levied and undrilled, thirdly to fight the battle before Scipio had recovered, but most of all to be up and doing and not let the time slip away resultlessly. For when a general has brought his army into a foreign country and is engaged in such a risky enterprise, his only hope of safety lies in constantly keeping alive the hopes of his allies.
Such, then, was the purpose of Hannibal, who knew that Tiberius was sure to be aggressively inclined.
Walbank Commentary