Shatapatha Brahmana 5.4.3.16

5.4.3.16

somāya vanaspataye svāheti | dvayāni vai vānaspatyāni cakrāṇi rathyāni cānasāni ca tebhyo nvevaitadubhayebhyo 'riṣṭiṃ kurute somo vai vanaspatiḥ sa yadeva vānaspatyaṃ rathasya tadevaitena prīṇāti dārūṇi vai vānaspatyāni rathasya dārūṇyevaitena prīṇāti kṣatraṃ vai somaḥ kṣatramevāsyaitadrājyamabhivimucyate

'To Soma, the wood-lord (tree), hail!' There are two kinds of (objects) coming from trees, the wheels of chariots and waggons, for both of these he thereby ensures safety. And the wood-lord (tree) being Soma,--whatever part of the chariot comes from the tree, that he thereby pleases. Now the parts of the chariot coming from trees are the wooden pieces of the chariot: hence it is the wooden pieces he thereby pleases. And Soma being the nobility, it is over the nobility that his kingship is thereby rendered free.