Soma-juice trickling from the sieve is compared with rain:
Rgveda 9.41.3: "The sound of the mighty Soma is heard like that of the rain; the flashes of lightning flash across heaven."
9.57.1: "Forward your streams are going, inexhaustable like the rains in heaven."
The pressed Soma purifies itself with flashes of lighning:
9.48.3: "... he, the Soma purifies himself with lightning, pressed in a stream, exhilerating Indra and the divine race (the devas)."
The receptacle in which the presssed Soma arrives is a lake
9.97.52: "... stream forth, o Drop, in the Mamscatva lake ... "
The Soma itself is a lake:
"From on high he (the god Indra) carefully perceives the lake (the Soma in the receptacle) ... "
The Soma is asked to "purify rain hither", i.e., it is asked that he, by purifying himself when he trickles through the sieve, should generate a parallel process in heaven so that it will rain:
9.49.1: "Purify yourself (o Soma) (so that you bring) rain for us, a wave of the waters from heaven, and healthy, large enjoyments."
9.97.17: "Flow (o Soma) for heavenly rain that moves rapidly, quenches (our) thirst, blesses the house, and gives quickly."
In addition several other comparisons are made, for instance the Soma is compared with a racing horse.
9.86.3: "Run (o Soma) as an incited horse to the prize ... "
9.97.20: "Let loose without reigns, without car, not yoked, as racing horses for the competition, these clear Soma-juices run forth. You gods, come here in order to drink them.