The men fought, moving from the bed to the floor, with the attacker still holding the hammer and the father elbowing, kneeing and punching him.
"I tried to put him to sleep with a choke hold to try to defuse the situation. I almost had him choked out - he was making a gasping sound - but I started running out of breath.
"I remember at this stage a lot of blood spurting out of his head.
"I eased off and said to him, 'What are you doing here?'
"He said, 'I was sent here.'
"I said, 'Who by?'
"He replied, 'The Lord sent me here.'
"I said to him, 'Mate you're f***** in the head.' "
Both men had a grip on the hammer.
"He had calmed a fair bit by this stage and was talking normally - almost being polite - asking for his hammer back." His partner and four children, aged 8 to 14, watched the altercation.
"We were standing up by now and I started dragging him out of the room. I was still trying to grab the hammer from him with my right hand and was holding his other arm with my left hand. He was trying to grab the hammer with both hands and I was trying to stop him.
"As I was dragging him out he went down and then came up and grabbed my nuts. He grabbed them really hard and it was really painful, but I had a lot of adrenalin.
"He'd released the hammer to grab my nuts and now I had hold of it. I whacked him three to five times with the hammer in the chest and maybe the face.
"I was whacking him to get him to release [me]. I didn't know what else to do.
"He let go ... and then I kicked him in a way to try to push him out of the room. He then shaped up to come back at me so I went to hit him again in the face with the hammer, but it slipped and I'm not sure if I hit him with the hammer or my hand."
The father stood over the attacker with the hammer and told him to leave. His partner helped the man out of the house.
When Hawke's Bay Today visited the home yesterday, blood was splattered on the bedroom floor and walls. He said his family was unable to sleep since the attack.
The family has rented the home for about 18 months. The father said the incident was "kind of a funny situation".
"I've never seen this guy before. But it was weird, it was like he's been to my house before."
Detective Senior Sergeant Dave de Lange said a forensic examination would take place and police would be talking with several witnesses.
Mr de Lange said that in an unrelated incident, a 37-year-old Napier man arrived at the City Medical at 5.30am on Sunday morning "with stab wounds to his head and torso".
"This man was also taken to the Hawke's Bay Hospital where he remains in a critical condition." Police yesterday were guarding the scene of the alleged attack on Hukarere Rd.
